The outpost door closed with an audible snick and Jack had just enough time to look at it over his shoulder before doubling over, almost retching as he tried to suck in fresh air to his abused lungs. Beside him, Teal'c was in a similar position, one hand on a hip, the other clamped around the base of his throat.

"You okay?" Jack rasped, suddenly concerned at the gravely sound of his voice. Teal'c simply nodded and started to stagger forward away from the airlock and in the direction of the distant control room.

"Jack! Teal'c!" The urgency in Daniel's voice demanded Jack answer, but he couldn't quite find the energy to reach his radio. Somewhere in the space of only a few minutes, he and Teal'c had managed to duck through the airlock system separating the Ancient outpost from the Yahut city, connect the barely functioning naquadah generator to the city's crippled power conduits, and get it online. Jack had silently been hoping for a fanfare of revelation or a choir of appreciative gospel singers to break into song the moment the city woke up, but nothing happened. No lights, no suddenly thrumming of power beneath their feet, nothing.

And they didn't have time to wait around for their fanfare.

They'd cut it close. Too close. There was air in the Yahut city, but it was stale and thin, barely enough to sustain one of them for a few minutes, let alone two of them. Jack gave little thanks to the fact that the central city conduit was only a stone's throw from the airlock, because as soon as the last door had closed and they were forced to breathe, the distance seemed unfathomable.

When it had become obvious the lack of air was affecting Jack and Teal'c's judgement, Sam had taken Daniel's radio and guided them through the whole procedure for setting up the generator and returning to the airlock.

Jack straightened up as best he could and fumbled for his radio. "Here," he croaked, uncaring if Daniel couldn't make sense of his words.

"Jack?"

"What!"

"You and Teal'c need to get back here now. Something's happening to the outpost."

"Again?"

"Look, I don't have time to explain, but you need to move!"

The emergency lighting dimmed as though it had taken its cue from Daniel's urgent plea to get his butt moving, and Jack suddenly found one of Teal'c's hands clamped down hard on his shoulder, pulling him forward towards the control room. His lungs felt torn and bleeding from the effort of simply trying to suck in the precious air they'd been denied, but the sight of one of the outpost room doors closing as they passed by pushed that pain aside.

"Teal'c!" Jack called out, jutting his chin at the door.

"I see it, O'Neill. We must hurry."

What Daniel didn't have time to explain had suddenly become incredibly clear: The outpost was sealing itself up, shutting down, and Jack had no idea why.

Teal'c and Jack flew through the control room doors as they snapped shut, landing heavily in a tangle of arms and legs.

"It's all in the timing," Jack heaved, flipping onto his back and throwing one arm across his eyes. "And if you dare say we cut that fine, Daniel, I swear I'm going to punch you."

"Not a word," Daniel said, kneeling down between them both. "But I'll give you a nine for your timing and a seven for artistic interpretation."

Jack lifted his arm a fraction and glared up at Daniel. "What? Only a seven?"

"Your execution of the flying and rolling maneuver needs work."

"Oy…" Jack let his arm slide to the floor and pulled himself up on to his elbows. "Anyone care to explain why doors kept closing behind us? Carter?"

Sam rapped both fists on the top of the Ancient console in frustration and dropped her chin to her chest. "I have no idea," she whispered just loud enough to be heard. "The system triggered a shutdown of the…" Sam's attention was taken by something on her laptop, and she peered hard at the screen. "Daniel, can you come here?"

Daniel was by her side in a few steps, and she moved aside to give him access to the computer.

"Ah," he said nervously, his gaze flicking between the laptop and the Ancient viewscreen, the same image now appearing on both. "This is not good."

"Talk to me, Daniel," Sam asked, placing a hand on his forearm.

"We've lost life support."

"What? How?"

Mikah was immediately by Sam's side. "I thought life support was a critical system?" he asked, squinting at the screen, but clearly not comprehending what he was seeing.

"It is," Sam replied and watched as Daniel tried to input commands into the console, hissing through clenched teeth when nothing he tried worked.

"Best I can tell, the outpost is shutting down non-critical systems in order to keep the more vital systems operational. Which makes no sense at all."

"Power conservation," Sam declared, pushing away from the console and slapping her right hand on her brow in frustration. "Ancient computers are intuitive and this one is probably working on the theory that the outpost has been completely evacuated. With no life to sustain, there's no need for life support."

"Time, Carter. How long do we have?"

Sam stepped up to the laptop and inputted an inquiry, teeth biting down on her bottom lip as she waited for an answer. "Not good," she mumbled, "We're on circulating air only, so about… 4 hours, maybe 5 if we limit our activity to only essential tasks."

"Essential tasks," Teal'c muttered and then cocked his head towards the door. "What of the jumper? Does it not have its own independent air supply?"

"You saw the inside of that thing, Teal'c. Barely enough room to swing a cat."

Teal'c raised one brow questioningly.

"Metaphorically," Jack quickly added. "It means we don't have a lot of room to spare. Either they didn't design this ship to double a lifeboat or..."

"Or?"

"The Ancients of the period were all midgets."

"The jumper!" Daniel pushed the laptop aside and studied the console, hands wavering over the top of the square blocks while he decided which one to push. Slowly, much more slowly than Jack liked, he selected a block and adjusted its level incrementally.

"Daniel… what are you doing?" Jack asked, instantly on his feet and suddenly very alert.

Daniel shot him a fleeting look, dark and unquestioning. Jack nodded tightly and left Daniel to figuring out the problem.

"This one." Daniel nodded at Sam and pointed to a block on the top right of the console, closest to her position. "Take it down one quarter, until the value on the screen reaches 6.18."

"What will that do?" Sam held her hand above the block and looked at the laptop screen. A number value flashed at her, bringing back memories of having a similar conversation with Ba'al at Dakara.

"The Ancients programmed in a series of command codes designed to override pre-determined programming in the event of a catastrophic failure. Remember? We talked about it earlier!"

"To overwrite any intuitive programming the computer initiates."

"Right! 6.18 is the frequency that holds the command code override to the automated doors. If we can't get them open, then we can't get to the jumper!"

"How do you know this?" she shot back, flexing her fingers above the block, hesitation coloring her voice.

"Sam!" Daniel reached over and knocked her hand away, pushing down on the block steadily until the readout on the laptop lowered to 6.18. The doors slid open behind him. "I don't know how long we can keep the doors open before the computer catches on to what we've done."

"Sir, you have to go!" Sam picked up the crystals they'd recovered and held them out to Jack. "You need to get to the sub-juncture at the tether and replace the crystals."

"Whoa, wait up. What about you and Daniel?"

"No choice, Jack. There's no way to tell if there's a command console at the tether. We need to stay and monitor your progress from here so we can manually reset the Stargate and get the ring generator operational."

"And regulate the amount of power passing through the sub-juncture once you've replaced the crystals," Sam added. "There's also a chance that the crystal housing itself or some other system at the juncture could be responsible for the feedback."

"Meaning?"

"Meaning Daniel and I will have to talk you through the repairs."

The plan clearly wasn't sitting well with Jack, and he shot them both a pained look as he grabbed the crystals. He nodded at Teesan and Mikah and thrust his head towards the door, a clear sign he was taking the two men with him. "So, replacing the crystals might not fix the problem? Is that what you're trying to tell me, Carter?"

She shrugged, a sour expression on her face. "Crystal degradation is the most likely problem, and replacing them should fix it completely, but we're talking about automated systems almost as old as Dakara. There could be other unseen issues. It's impossible to be accurate, sir."

"Jeez!" Jack swore through a suffering groan. "Is there anything we're certain about here? Anything at all?"

"I'm reasonably certain if you can get to the tether then the amount of viable oxygen left in the outpost should be enough for Sam and I to survive on while you're gone."

Jack frowned at the tinge of cockiness in Daniel's tone, and countered back, "Which assumes there's an air supply at the sub-juncture, right?"

"You'll know once you dock at the tether, sir," Sam interjected quickly. "The Ancients obviously used the jumper for deep water maintenance on both the outpost and its other mechanical systems, so it's safe to assume it has the capability to relay environmental conditions at its destination."

Jack waved a hand at the Ancient viewscreen. "And you can't tell all that from here?"

"No, sir." Sam turned to face the screen. "In fact, we haven't been able to glean much information about the sub-juncture at all, save knowing that it actually exists."

"A bit odd, isn't it?"

"I think so, yes, but it could be something as simple as the outpost computer not being able to monitor the equipment there anymore due to some technical malfunction. We haven't been able to access an interior schematic of the core, either."

Daniel pushed his glasses back on his head and rubbed at his eyes. "Actually," he mumbled from under his hands, "it's a miracle the Yahut managed to survive this long, considering the condition of the outpost. This place really should have shut down decades ago."

"Yeah, well… funny how we turn up and it all goes to hell in a hand basket," Jack grouched. "Famous SG-1 timing?"

"Maybe," Daniel conceded wryly, "but I think Zolan will be thanking us for getting his people out of here before the situation got to the point where they couldn't leave."

Jack took a long, lingering look at the viewscreen and tossed a thumb over his shoulder to where Teal'c and the two Yahutians stood waiting for him. "Speaking of leaving… I guess we should…"

"Yeah," Daniel smiled thinly. "Good luck."

"You, too."

~oOo~

Less of a ship and more of a bath tub, Jack thought as he struggled with the controls of the Ancient submersible. The craft felt heavy and sluggish under his touch as he guided it away from the outpost, swinging on a large right-turning arc away from the city to come back on the tether. To his right, Teal'c sat in the co-pilot's position, his posture stiff as he surveyed the instrument panel and then lifted his gaze to the forward window.

"Got it figured out yet?" Jack asked, not really wanting conversation when his attention was so acutely fixed on keeping the ship from flipping over, but slightly nervous at Teal'c's long silence.

"This does not feel right, O'Neill." Teal'c rested his hands on the console, fingers splayed.

"Yeah. I'm worried about leaving Carter and Daniel, too."

"It is not that which concerns me. Colonel Carter and Daniel Jackson are more than capable of guiding our descent and looking after their own well-being."

"Oh. Well, yeah. So?"

"I find the variables of this mission to be much higher than we have encountered in the past. Could it be that we were wrong to attempt to save this world?"

"Call it hindsight, Teal'c." The tether loomed large in the viewscreen and Jack had to manually slow the ship's approach by pulling back on the controls. His first interaction with the jumper when they'd gained access through the rear hatch had instantly told him what they'd all suspected: This model of jumper, unlike its younger sister, didn't employ a neural bond with an ATA carrier to operate. For some reason that should have thrilled him, he liked the tactile feel of maneuvering a vessel and knowing that it only went where he directed it, but this was different. Whether it was knowing they were underwater, or from the imposing pressure bearing down on them, but Jack couldn't quite get the little ship to do exactly what he wanted.

The tether glided by on their right side, long strands of red and purple seaweed wrapped around its girth and swaying madly in the current produced by their passing. Jack pointed the craft downwards and, after a few seconds of trial and error, managed to activate the forward floodlights, illuminating the ocean beyond. Behind him, Teesan and Mikah were sitting on the edge of their seats in what passed for a passenger section, staring open-mouthed at the incredible vista outside the jumper. In truth, they were perched on benches that were probably designed more for storage than anything else. Jack hated being right, but it was fairly self-evident that the little ship had only been designed to carry a very minimal crew and for only a short period of time. Compared to the jumper they'd recently liberated from Harry Maybourne's world, and the images of the ones the Atlantis team had discovered, this one was barely half the size.

Jack looked at the reflection of the rear of the ship on the viewscreen and frowned. He doubted this ship had the life support to carry four people, let alone six, should this suddenly become their lifeboat.

"Ahead at your eleven o'clock, O'Neill." Teal'c pointed to a spot just to the upper left of Jack's left shoulder. He'd been daydreaming and wasn't watching their decent vector on the viewscreen and had almost missed the boxy protrusion clinging to the tether. This time, Jack was forced to break off their decent and swing the craft to the left to avoid a dense patch of purple seaweed. The growth was thicker than what they'd seen before and almost completely obscured the sub-juncture building. He swung the ship around in a tight circle, gliding it from side to side as he navigated a path through the seaweed, and stirring up nest after nest of small fish-like creatures that were clinging to the gnarled tendrils.

"There," Teesan called out from behind Jack's shoulder, his hand just waving past his nose and towards the sub-juncture. "There is a circle on the side. Could that be some sort of docking port?"

"I see it," Jack replied, pulling the nose up and forcing the ship into a tight one hundred and eighty degree turn to present it hatch first to the dock. Without prompt, the image on the viewscreen changed to a close-up view of the airlock and showed Jack his approach angle.

"Huh!" Jack said using finger pad controls on the steering arm to kill the engines and activate the ships small maneuvering thrusters. "How did it know I wanted to see where I was going if there's no neural interface?"

"Perhaps there is a proximity device on both the ship and the station that detects the other's location and activates a guidance system for the pilot," Teal'c suggested.

"Like the back-up camera on my truck?"

Teal'c gave Jack a sideways glace, one eyebrow cocked high on his forehead. "A slightly more sophisticated version."

Jack stared at him deadpan for a moment before turning his attention back to the viewscreen and the airlock they were about to engage. "Five feet," he announced firing the port side thruster to compensate for a slight degree of drift. Out the window, he caught a tight swirl of water and air bubbles as the thruster helped guide the ship into position.

"Two feet."

Metal on metal, the noise reverberating through the cabin for a few seconds, and the airlock snapped onto the back of the jumper, a blue light on the right side of the hatch signalling a tight seal. Jack tapped the locking mechanism on his safety harness and slid out of his seat, announcing in his best airline hostess voice, "Ladies and Gentlemen, Air O'Neill thanks you for your patronage and wishes you a safe onward voyage."

"Where are we going?" Mikah asked. "Is not the sub-juncture our intended destination?"

"Ah, yeah…"

"I do not believe the Yahut recognize your particular form of humor, O'Neill."

Jack looked from Mikah to Teesan, at their confused but expectant looks, and then across to Teal'c. "Ya think?"

To Be Continued...