"Jesus, David, where did you get that?"

Nothing could have prepared Scully for the shock that awaited 
her when she descended into her underground lab.  The main 
bench had been cleared completely of equipment, and a 
desiccated Gray corpse lay rigid under the bright central 
light.

David's posture was nearly as stiff as the corpse, tight and 
defensive.  "I wasn't expecting you back yet," he said.

Wary, he watched her approach the cadaver, expecting a 
lecture at best, a repeat of their last, furious argument at 
worst.  Instead, she pulled a pair of disposable gloves from 
a drawer in the bench, and snapped them on.  He watched her 
as she moved around the body, delicately prodding the dry 
flesh, examining the ancient neck wound.  When she looked at 
him again, he found himself at a loss.  The moment he had 
determined to collect the body he had begun steeling himself 
to withstand her outrage.  Now, it appeared that it would not 
materialize, and he was unsure how to react.

"How did you get it here, David?" Scully finally broke the 
silence.

Cautious, he answered, "I stowed away with it on a cargo 
tube."  He was interrupted by the need to sneeze.  The cold 
he'd been fighting for the past week had made his excursion 
into the mountains particularly unpleasant.  "It was wrapped, 
of course," he added, when he had cleared his head.

"Of course," she repeated.  Breaking eye contact, she 
returned to her inspection of the body.  "Where did you find 
it?"

"Norad," he answered.  "The place where I found your cross."

Scully laughed, a harsh, humorless bark.  "Well, then, I 
guess we've met."

He waited for her to say more, and at last offered, "I 
thought it was too valuable a resource to ignore.  The 
opportunity to examine tissue samples will accelerate the 
research."  He paused, then added, "Yours too, not just 
mine."

Scully ceased her survey of the dead Gray and stripped off 
the gloves.  "No, David," she said, "Ours.  I think you're 
right, we have to concentrate on finding a weakness to 
exploit.  The human population is at risk, and we haven't the 
means or the time to protect them while I pursue my 
solution."  

"What changed your mind?" David asked, astonished.

"An old friend," Scully said.  "Never mind.  We'll learn what 
we can from the body.  But David, exploiting a weakness does 
not have to mean extermination.  We'll work together, but 
toward a goal that stops short of that.  Can you at least 
meet me halfway on this?"

He replied with a grave nod.  He was relieved to have her 
cooperation again, relieved to have an end to their 
increasingly hostile interactions.  Later, he would realize 
that he was also relieved to be in pursuit of a less 
bloodthirsty solution.  He was still poisoned by the Grays' 
betrayal, but in his soul, David was not a murderer.

"Come over here, David," Scully said.  

David complied, crossing around the bench to stand in front 
of her under the bright lights.  She reached for his face, 
pulling the soft skin beneath his eyes downward with the pads 
of her fingers.  "Look into the light," she instructed.

David crouched slightly, to give her better access.  "What 
are you looking for?" he asked, rolling his eyes toward the 
ceiling.

"Did you see anything that looked like a black oil where you 
found the body?" Scully asked.

"Yes," he said.  Scully let go of the first eye, and repeated 
the inspection on the other side.  

"Did it touch you?" she asked.

"No.  It moved toward me, but then it stopped, and moved away 
again."

Scully released him, satisfied.  "It must have sensed the 
vaccine," she said.

"What was it?" David asked.

"We were never completely sure.  It's a biological component 
of the Grays, and it seems to be able to live on even when 
the body dies."  

"I should have collected a sample, then," David said.

Scully shuddered.  "No, it's better that you didn't.  It's 
nearly impossible to contain.  I think you brought back quite 
enough."  She looked again at the small, pale body.  "Come 
on," she beckoned him, "I need you to help me get some old 
equipment out of the deeper storage."

He followed her out of the lab enclosure, frowning as the 
damper air of the cave irritated his sinuses.  Back in a dim 
corner, Scully gestured toward a six-foot slab of stainless 
steel that still gleamed dully in spite of its long residence 
in the moist cave.  The collapsible stand had not fared quite 
as well, the bearings groaning as she wheeled it back to the 
lab, the joints resisting being raised and locked into 
position.

Together they set up the autopsy table in the lab and 
transferred the ancient corpse onto it.  The gray body seemed 
dwarfed, almost childlike, on the tray.  

David had thought he was prepared to take the step from the 
sterile world of microbiology to the reality of invading a 
body, but his thinking had been much too limited.  Needle 
biopsies, collecting small samples of tissues and cells to 
incubate and examine, had been as far as his imagination had 
taken him.  He wasn't ready for the rack of tools Scully 
pulled out.  The array of scalpels was only mildly 
disconcerting, but the bone cutters and saws unnerved him.  
They looked barbaric, sitting mute on the tray.  When they 
came to life in Scully's hands, tearing into the Gray's 
cranium with a protesting whine and the scent of smoke, David 
tasted the unmistakable flavor of bile in the back of his 
throat.

"No zipper," Scully cracked, succumbing to a moment of 
gallows humor.  She held up the bowl of bone to show David, 
and noticed his blanched and sweaty face behind the curved 
plastic of his face shield.  "You're not going to faint, are 
you?" she asked.

He shook his head, and resolutely raised the small digital 
video camera he was holding.  "I'm fine," he insisted, 
although it was an obvious lie.  Sometimes, Scully saw so 
much of both herself and Mulder in David that she wondered 
how she could ever have missed the fact that they were kin.

The body was in surprisingly good condition, in spite of its 
long entombment.  It was dehydrated, but there was very 
little decay.  Scully kept up an unrelenting monologue as she 
worked.  Some of the organs were mysterious, but others were 
reassuringly familiar.  The lungs were obvious.  So was the 
stomach.  There seemed to be a circulatory system of some 
kind, but she couldn't identify anything like a heart.  
Instead, the artery walls themselves appeared muscular, the 
pumping mechanism fully distributed.

For the second time since they had met, the nature of 
Scully's research underwent a fundamental shift.  The once 
painful and tedious reverse engineering from an endless and 
unannotated sequence of base pairs had become the task of 
separating the jumble into the most likely combinations for 
three separate species.  Now, with a complete specimen 
available to them, aged though it was, the task was to match 
the systems to their genetic coding.  And having spent a 
lifetime as Dr. Luder, Compartive Genomics virtuoso, this was 
a process at which she excelled.

-------------------------------------------------------------

Only a few days had passed when Scully reached a startling 
conclusion about their new roommate.

"David, look at this tissue."  Scully turned the microscope's 
monitor toward him.  

David indulged in a mighty sniffle before crossing over to 
see what she was showing him.  "Is that from the lungs?" he 
asked.

"Yes.  Look here.  This type of cellular damage is what we've 
been seeing throughout the body, probably from the aging and 
dehydration."  She pointed to another spot.  "But this is 
different.  It's almost appears to be a sort of cellular 
scarring."

"Is that an alveoli?" he asked.  Wherever the Gray's system 
approximated known physiology, they used the familiar terms.  
They had determined this tiny air sac to be central to the 
exchange of gasses into the circulatory system, just as in 
most mammals.

"Yes, it is.  I think this Gray was very ill.  The neck wound 
is the obvious cause of death, but I don't think it can have 
had a very easy time breathing.  Maybe that's why it failed 
to overcome the soldiers in the air shaft at Norad."

David leaned in close and peered again at the scarring on the 
monitor.  "Do you think this represents an existing illness 
at the time of death or something it had already recovered--" 
His sentence came to an abrupt stop making way for an 
unexpected, forceful sneeze.  "Sorry," he apologized, as 
Scully reached for a disposable wipe to clean her face.

"You know David, I wish you'd cover your mouth when you do 
that," she frowned.  "I may be immortal but I'm not immune 
to..."  She trailed off, overcome with an idea.

"That's it!"

"That's what?" David asked, wiping his nose.

"The answer.  The middle ground.  How we're going to get the 
Grays to leave Earth, once and for all."

David shook his head, not following.

Scully went on, warming to the plan forming in her head.  
"Look at the pieces we have.  Evidence that they're 
susceptible to respiratory trauma, disease.  An adversary 
that didn't evolve it's immunity in the viral and bacterial 
background noise of this planet.  We've been thinking in 
terms of tailoring a solution that attacks an alien 
physiology we only partly understand.  Instead, we should be 
thinking about the biological arsenal this planet already 
has, that we already understand.  That's our target."  She 
thrust an index finger into her palm for emphasis.  "We need 
to compromise their immunity so that every little bug causes 
a severe reaction.  Every time they step outside they'll be 
inviting their equivalent of pneumonia or asthma.  We're 
going to give them a savage, inescapable allergy to Earth.  
If they want to save themselves, they'll have to leave."

David nodded.  The plan had merit.  "Immunity is one of the 
best studied sub-fields.  We'd be working to our strengths," 
he concurred.

"Delivery will be a problem, though," Scully remarked.  "Even 
when I was Dr. Luder, I never came across any transoceanic 
mosquitoes with a taste for Grays."  She flashed a thin smile 
at her joke, and became serious again.  "It's the wrong time 
of year for an ocean crossing, but assuming we could get one, 
that's close to two weeks to Europe at the very least.  And 
then would it be better to cross into Africa from Spain, or 
tube around the Mediterranean?" she mused.  "African travel 
would be overland, unless we could hire a boat on the Nile."  
Her head swam with the logistics involved in getting to the 
Grays' settlement.  She couldn't see any good way to get 
there unnoticed, and with their payload intact. She shook her 
head.  "I wish we still had aircraft."

"No," David said, realizing with sudden clarity the only 
viable approach.  "We don't go to them.  We let them to come 
to us."

Scully waited, unsure what he had in mind.

"This immuno-suppressive agent we're going to develop has to 
be a virus," he said.  "As contagious as possible.  And then 
we have to infect abductees."  He delivered the last sentence 
in a rush, certain she would hate the idea.

"A Trojan horse?" she asked.

He nodded, remembering the old fable.

"Risky," she finally concluded.  "If we design it to survive 
in a human host, we risk a pandemic in the human population."

"We'll design it so that humans are just carriers."

"Just carriers until it mutates.  Once you set something like 
this loose in the wild, there's no taking it back."

David's expression was troubled, but determined.  "You're 
right, there is that risk.  But there's always the risk of 
new disease, and at least we'll be taking every precaution."  
He thought of Amy, how he would feel infecting her, and then 
considered the alternative.  "I don't like the idea of human 
hosts any better than you do," he confessed, "but I think the 
stakes are high enough that we have to chance it."

Scully nodded her concession.  She was proud of David for 
learning how to weigh such heavy options without being 
paralyzed by the consequences.  She was also deeply sorrowful 
that he should have to.

-------------------------------------------------------------
David counted the Grays' arrogance as a small piece of luck.  
Fully engaged in their own program of experimentation, he and 
Scully seemed to have fallen off their radar.  Ever since he 
had uploaded the final, incorrect separation of species to 
the net, David had felt no further probing from the minds of 
the Grays who had occasionally watched them.

The Grays had stopped watching Scully before her change of 
heart regarding the approach resistance should take, and he 
had guarded his own thoughts carefully.  They were unaware of 
any viable threat.

And after several weeks of work, the threat *was* viable.  
Sequestered as they were, only David's telepathy gave him any 
insight into the progression of the abductions.  The largest 
groups had numbered around thirty.  Even without an 
understanding of the cause, the disappearances should have 
generated a stir on the news nets, but as far as David could 
tell, knowledge of the events was only spreading by word of 
mouth.  Most minds he touched remained content, and unaware.

But the minds of abductees were tortured, tormented by an 
unidentifiable fear.  Sounds, shapes, lights and smells, any 
of these could trigger panic that could not be explained.  
Until the next time they were abducted, and the reality of 
being aboard the Gray ship shattered the memory block.  
Scully had given him a peculiar look when he had suggested 
adding a sedative to the formula they were developing, but 
had acquiesced without argument.

They had prepared four multiple-dose injectors with enough 
serum to treat approximately sixty adults, delivering the 
vaccine, the virus, and a few hours peace in a single shot.  
For several days now, they had merely been waiting for their 
moment.  

David could feel the proximity of the Grays as they 
approached and receded, picking up subjects from different 
parts of the continent.  Tonight, he felt them near, near 
enough to make their move.  He rolled out of bed, collecting 
the two small parcels containing the injectors and the alien 
weapons, and went to wake Scully.

"David, what is it?" she asked, groggy with sleep.

"It's time.  We have to go.  They're heading for a site here, 
just outside Seattle.  We can make it if we hurry."  He 
handed her one of the packages.

"How do you know?" she asked, never the less grabbing her 
shoes and a parka as she came awake.

"I just know," he answered.  "Trust me."

She nodded without hesitation.  It was time to let him lead.

They hiked through the deceptively peaceful night, speaking 
little, lost in the tension of their mission.  Scully was 
surprised when they encountered the first of the abductees.  
He was barefoot, and dressed in bedclothes, hurrying along 
the path in front of them.  He gave them a blank, puzzled 
look when they caught up to him.  "I think I'm late," he 
murmured, but didn't explain to what.

They trailed him at a discreet distance.

"Oh, my God," Scully exhaled when they reached the edge of 
the woods.  The belly of a Gray ship hung heavily, 
expectantly, above the meadow clearing.  Beneath it, people 
milled about, staring upward, gradually seating themselves in 
perfect columns and rows.

"There's one more thing," David said, turning to face her.

"What?"

"You're too loud, Scully.  Mentally.  Your tension and 
anticipation -- if they turn their minds toward us, you're 
going to give us away."

"What do you want me to do, David?  Think about pink 
elephants?" she asked, frustrated.

"No, I don't think you have enough control," he answered, 
ignoring her sarcasm.  "You can't go any closer, you're like 
a beacon right now."

"And you're not?" she retorted.  "I'm not letting you go 
alone, David.  I'm less vulnerable than you, and you need 
someone to watch your back."

"I know," he conceded, reaching for her hand.  "I'm sorry."

"Sorry for what?" she asked, then felt the sharp sting of an 
injection along her wrist.  "What did you do?" she began, but 
her eyes rolled back in her head, and he caught her as she 
slumped.

"It's only for a little while," he promised her unconscious 
form.  Gently, he hoisted her to his shoulder, and emerged 
into the clearing.

-------------------------------------------------------------

When Scully awoke, it was to the sensation of a cold, 
metallic surface under her cheek, and the sound of a deep, 
inescapable thrumming.  She sat up with a gasp.  David's face 
swam into focus, his breath escaping in a long sigh of 
relief.  

"How long?" she asked.

"About fifteen minutes.  Are you okay?"

Scully scrubbed her hand over her face, and blinked twice.  
Surprised, she realized there was no residual fuzziness from 
the sedative.  David must have chosen one that metabolized 
quickly.  "Fine."  She looked at him.  "We're even for that 
business with your tracker now, right?"

He grinned in return, wired with adrenaline.  "Maybe."

"We're on the ship?"

"Yeah," he nodded.  "Africa bound.  With the rest of the 
cargo."  

Scully's eyes adjusted to the dim lighting, and she leaned 
sideways to see past David into the space beyond.   It was 
remarkable in its lack of features.  The walls, floor and 
ceiling were a dull, flat metal that failed to reflect any of 
the dim light glowing from a band ringing the room at the top 
of walls.  Only the light it emitted distinguished the band 
from the wall that contained it.  The surface and material 
was otherwise homogenous.  There were no sharp corners.  At 
the floor and ceiling, the walls bent in a gentle curve.  It 
was like being inside a brushed aluminum egg.  Gradually, she 
recognized the shadowed forms as other passengers, huddled in 
small groups, clinging together in fear.

"Thirty three, including us," David answered her unspoken 
question.  "They listened in on everyone as they brought them 
aboard, but they're done with us for now."

Scully's brows furrowed as she processed his assured 
recitation about the Grays' attention.  "David, can you hear 
them?" she asked.

"Yes.  I've heard them for a while," he confessed.

"Why didn't you tell me?"

"You knew, at first.  Jerry made you forget."  Her eyes 
widened with his admission.  "You agreed to it.  It was to 
protect me.  Look," he deflected, knowing she wanted to hear 
more, "We don't have time to get into this now, but you'll 
start to remember soon, I promise."  He pulled an injector 
out of his inside pocket.  "It's a short trip.  We need to 
get started.  Are you ready?"

Scully nodded, following as David crept toward the nearest 
forms she could see.  

"Hi," he said to the young man he approached.  "Okay if I sit 
here?"

The man shrugged, the dim light glinting off the whites of 
his eyes.  He said nothing, but gripped the woman he held, 
her face buried in his chest, a little tighter.

"My name is David," he offered gently.  The man seemed to 
emerge slightly from his fugue, focusing clearly for the 
first time on David's face.  After a moment he looked at 
Scully.

"Who are you?"

"I'm Dana," she said, surprising herself with the old name.  
She shrugged mentally.  Back in the heart of this ancient 
battle, who else would she be?

"I'm John," he answered. "And this is Lainie," he gestured to 
the woman in his arms.  She was shaking visibly.  

"What's wrong with her?" Scully asked.

"She's scared," John answered.  "This is the fifth time for 
her.  I try to comfort her but," he bit his lip, hard, a 
single anguished tear breaking free, "I'm scared too."  His 
voice thinned to a helpless squeak, and he began to rock 
slowly back and forth.

"John," David said, "I can help."  

The young man continued rocking, his stare glassy.  

David leaned forward and took his shoulder, stilling him.  
"John," he repeated, his voice rich with compassion, "Let me 
help."

"How?" he whispered, meeting his eyes once again.

"I'm a doctor, John," David said.  It was nearly true.  He 
could have graduated this week.   "I have something that can 
take the fear away."  Slowly, so as not to startle, he 
revealed the injector.  "Do you want it?"

John looked from David's eyes, to his hands, and back to his 
eyes again.  "Yes," he whispered.

"Okay, good," David soothed.  "I'm going to put this on the 
side of your neck, here," he demonstrated on himself, "and 
then you'll feel a little sting.  That's all.  In a few 
minutes, you'll feel better.  Are you ready?"  

When John nodded, David leaned forward and administered the 
preparation, never breaking eye contact.  The effect of the 
sedative was dramatic, tension draining visibly from John's 
body, and sanity returning to his gaze.  

"Thank you," he said, "Thank you."  He relaxed back against 
the wall, pulling the woman into his lap, stroking her hair.  
"Could you help her, too?" he asked.

"Of course," David answered.  "I'm going to help everyone."

-------------------------------------------------------------

As David moved throughout the stark hold, the timbre of 
voices changed gradually from stifled moaning and gulped-back 
tears, to muted conversation.  

After treating several more passengers as a team, David and 
Scully had split up, circumnavigating the room in opposite 
directions, dividing the effort so that they could treat the 
abductees as quickly as possible.  Although Scully treated 
nearly as many as David, their eyes tended to follow only him 
as he made his way around the chamber, talking and 
reassuring.  He was reaching them in a way she wasn't.  
Whether it was because of his gift, or because after all, he 
was their contemporary, and she was not, Scully couldn't 
know.  But it felt strangely right that they should turn 
their hopes to him.  She remembered her presentiment that day 
in the Cathedral, that he would be the one to lead this 
struggle.

"This is Anna," David said, as he and Scully met again at the 
place where they had begun.  A small, blond girl of perhaps 
five or six years clung to his neck, regarding him with 
obvious adoration.  She was by far the youngest of the 
abductees.  "Anna, this is my friend Scully."  

Anna flicked her eyes away from David long enough to give 
Scully a cursory inspection, but said nothing.

"Come on, Anna, let's sit down, okay?" David said, moving 
toward a vacant spot against the wall.  Cupping both hands 
carefully around the shell of his ear, Anna whispered a 
question.  He smiled and nodded, rearranging her carefully so 
that as he sank to the cold floor, Anna came to rest centered 
on his lap.  Trusting, she laid her head against his chest 
and closed her eyes.  

The ever-present thrumming changed pitch abruptly just as 
Scully sat down beside them.  

"Almost there," David said.

"Do you know what happens when we land?" Scully asked.

David shook his head.  "Not exactly."

"They'll move us."  The woman, Lainie, one of the first they 
had treated scooted over, closing the few feet of space that 
separated them.  "They'll keep us in the zoo until they're 
done with us, then they take us back."

"The zoo?" David repeated.

"There's an encampment, with a high, charged fence," she 
explained.  "In the middle there's a building, a place you 
can get away from the heat, but the walls are mostly glass, 
or something.  You can't hide anywhere.  They're watching you 
all the time."  She shrugged.  "Like a zoo."

"How do we get from the ship to there?" Scully asked.

"We walk," Lainie answered.  "They send in a troop of Smiths, 
mostly the tall, bulky ones, you know them?  Anyway, they all 
have weapons, long metal sticks with some kind of charge 
emitter on the end.  If they touch you it's agonizing."  She 
shuddered and fell silent with the memory.

"Lainie," David prodded her from her reverie.  "How far is 
the walk?  How many guards?"  

"You can't escape, if that's what you're thinking," she said.  

"What happens after we get to the zoo?" Scully interjected.  
"How long do we stay?  What happens while we're there?"

Lainie studied Scully carefully for a moment, then looked 
back to David.

"What are you two doing here?" she finally asked.

"What do you mean?" David said, as innocently as he could 
manage.  "We're here the same as you."

"No," Lainie intoned, "not the same.  I've been here five 
times.  You're not the same at all."

"I don't know what would make you think that," David said, 
wondering what he and Scully might have done to have blown 
their cover.

In his lap, Anna opened her eyes and pushed her tiny hands 
against David's chest, so she could look him in the face.  
"Because," she said, "you're not asking *why*."

"Shh," David said, smoothing the child's hair and urging her 
to relax into him as she had done before.  

"Out of the mouths of babes," Lainie said, when David 
returned his attention to her.  She reached forward, slipping 
the empty injector from his pocket.  "You knew to bring 
this," she held the device up between them, "and you're not 
afraid.  You're more than you seem.  Was this more than it 
seems, too?"

David reached out, and gently slid the injector from her 
loose grasp, returning it to his pocket.  "It's just a 
coincidence," he said.

"It's because they get inside our heads, isn't it?" she 
asked.  "That's why you won't talk about it."

Out of excuses, David only stared in response, his face 
bland.

The thrumming abruptly raised in pitch and intensity, before 
falling silent altogether.  There was a slight bump as the 
ship settled to the ground, then the band of lights dimmed 
and went out.  David felt a swift, unexpected pressure 
against his lips.

"Thank you for trying," Lainie's voice whispered against his 
ear.

A crack of daylight, harsh after the weak light in the 
chamber, broke and widened at the far end of the room.  David 
squinted, his eyes slow to adjust, the guards appearing in 
silhouette against the backdrop of the widening doorway.

Slowly, people began rising to their feet, preparing for the 
short march to the holding facility.  The guards entered the 
chamber, herding them into a tight group and surrounding 
them.  People shuffled and moved, finding their position 
within the press, and as if by some unspoken agreement, the 
abductees shifted and jostled David and Scully to the very 
center, expressions of protectiveness and determination plain 
on their faces. 
-------------------------------------------------------------

From their vantage point in the "zoo" David and Scully had an 
unprecedented view of life in the Grays' colony.  To the 
north, what appeared to be several huge ships seemed to have 
been permanently embedded in the African plains, rising 
dozens of stories out of the ground, and obviously 
functioning as the heart of the settlement.  Around these, a 
small city had grown up, the buildings constructed of native 
materials and evidently homes to the attendant Smiths.  
Aliens of both species could be regularly observed moving 
about the compound.

To the west, a fleet of small, nimble ships was moored.  
Several of these left and returned during their first day.  
One collected and took away the previous group of abductees, 
but the purpose of the other flights was unclear.

The "zoo" itself was aptly named.  There was little to eat.  
Bins of fruit were piled unceremoniously at the far end of 
the yard, near a trough running with fresh water.  There were 
no facilities for elimination, and no privacy.  The opposite 
corner of the yard was used when the need could no longer be 
postponed, with people doing their best to cover the stinking 
mess with handfuls of the hardscrabble dirt.

Every few hours, a Gray arrived with four Smiths, and 
selected several subjects to be taken from the compound.  
Lainie had been among the first group taken after their 
arrival, and still defiant with the remains of the drug, and 
the glimmer of hope, she had spit in the Gray's eye.  David 
had been pleased with her temerity.  Mucous membranes were an 
excellent conduit for transmitting infectious agents.

The sun was setting on their second day in captivity, when 
Scully abandoned her observations and crossed the compound to 
join David, in the relative comfort of the squat, cooled 
building.

"I'm not seeing any effect yet," she said, by way of 
greeting.

"Incubation will take time," he answered.  "I'm still 
confident."

Scully licked her lips, chapped from two days under the dry, 
African sun.  Her face was well burned, her arms only 
slightly less so.  "Have you been able to hear anything about 
our return trip?"

He shook his head.  "Not specifically.  But they've treated 
two thirds of our group.  If the pattern holds, I think we'll 
be returned tomorrow."

"And us?" Scully asked.  The question had hung unspoken for 
two days.  David must have known her concern, but since he 
hadn't addressed it, she pressed him by asking aloud.

"We're not actually on the inventory.  I doubt we'll be 
tested.  We're just two lab rats among dozens here, and not 
the ones they're looking for."

"And where does that leave us when they pack up the 
experiment?"

"I can get us on the ship, Scully, don't worry."

But she did worry.  They had discussed the risks of 
infiltrating the Grays' colony during the weeks of refining 
the virus.  Being taken for tests was one horrific 
possibility, but they reassured themselves with the knowledge 
that ultimately they would survive the experience.  For 
Scully, living for eternity in this damn zoo was becoming the 
more unpleasant prospect.

"There," David pointed.

Scully squinted against the glare of the low sun on the glass 
of the building, in the direction David indicated.  Another 
collection party was heading for the compound, but something 
appeared wrong with the Gray.  It stumbled, then collapsed to 
its knees.  One of the attendant Smiths caught it by the 
elbow, supported it while an explosive shudder wracked its 
body.  The Smiths consulted tensely with one another, then 
hoisted the Gray to its feet, supporting it under the arms.  
The Gray's head tilted back, revealing its face to David and 
Scully for an instant before the Smiths swung him around, and 
headed back toward the largest of the seated ships.  A thick, 
green-brown viscous substance was oozing from its tiny 
nostrils.

"Hypothesize, experiment, observe the results," David 
intoned.  

Scully allowed herself a small moment of relief.  They 
wouldn't have to make another of these excursions with a 
modified formulation of the virus.  Two hundred years ago the 
resistance had been a bloody, worldwide affair.  This time it 
was small, focused, surgical, and would be a success.  It was 
almost over.  All that was left was to get home.  She was 
suddenly exhausted.

"You sleep, I'll watch," David said, reading her.  He offered 
her a brief smile.  "You think too much, anyway."