Carson panted for breath, stumbling along in Ronon's wake. His legs already felt like jelly. He tried to tell himself that it was from the lack of sleep and food, the stimulants he'd been taking for too long now, but he had an unfortunate sneaking suspicion that it couldn't all be blamed on the circumstances. Carson wasn't really one for fieldwork, or exercise, and his favorite outdoor activity was sitting on a rock and waiting for a fish to swim too close to his lure. He was not prepared to run at top speed through Atlantis, especially not with Ronon.

"You and the Colonel really do this for fun?" Carson gasped. Ronon turned around to glare at him, not breaking stride.

"Save your breath."

"Go...right," John said into the comms. Carson frowned. John's pause had been disconcertingly long. Carson wasn't sure if he just didn't know what he was doing, or if there was something else going on. John's voice seemed to be getting weaker by the second, and Carson could hear him struggling to draw breath even through the commlink.

"He's quite badly hurt, isn't he?" Carson asked quietly, half-expecting Ronon just to yell at him to stop talking and keep running.

Ronon glanced back again, but instead of the scowl Carson had expected, Ronon just looked sad and scared.

"Ronon, what's happened to him? Tell me how badly he's injured. I need to know, son."

Ronon looked as though he were wavering, and then he shook his head. "Can't. Sheppard doesn't want me to."

"Damn it, I'm his bloody doctor," Carson snapped. They were all going to die in an hour, and for all he knew, John could be dead much sooner than that. He wanted to know what was happening to his friend.

Ronon shrugged. "He wouldn't tell you earlier."

Carson groaned, feeling a sudden - and rare - flash of anger. John was exercising his typical brand of stubborn insanity, and he'd managed to pull Ronon in too. The Satedan was deeply loyal to the Colonel, Carson knew that, but this time he was afraid it was at the expense of John's health. Even if he couldn't do anything right now, maybe he'd be able to tell Teyla how to help, he could think through the problem on the way….

"Sorry," Ronon said, his voice unexpectedly sincere. "You gotta focus on this, Doc."

Carson sighed, the anger vanishing as quickly as it had come. Ronon and John were right. He'd already managed to distract himself by worrying over John's welfare, but he needed to stay focused on Elizabeth. Ronon couldn't afford the distraction, either. Still, Carson couldn't help but worry.

"He'll be able to last the hour?" Carson asked, half-dreading the answer.

"If I thought he wasn't, I'd carry him to you myself," Ronon said, eyes darkening.

"Please, just let me direct them," Teyla begged. John groaned and let his eyes slip closed. The pain in his head was continuing to build, and he was having trouble staying focused on the map in front of him. He was having even more trouble actually processing where Carson and Ronon were in relation to the Nanite Lab. The idea of somehow accurately conveying to Carson and Ronon where they needed to go? Impossible.

Or, as it turned out, all but impossible. Because he had been doing it. They weren't lost yet, as far as he and Teyla could tell.

But John was fading fast. All he wanted to do was close his eyes. The pain in his leg had grown to such unimaginable levels that it hardly felt like pain anymore. It felt like...fire, like numbness. He had no sense of time anymore. He may as well have had the encounter with the Replicator years ago. His body was a prison that he would be trapped in forever, and it was starting to fall apart around him.

"Fine," he said to Teyla. She opened her mouth - apparently preparing to argue, but then realized that he'd agreed. Instead, she just sighed.

"Continue down that same hallway until you reach a set of stairs," Teyla said.

John understood why she was confused. John was not one to give into anything without a fight, even something as simple as this. But he was...exhausted, so tired and broken on such a deep level he wasn't sure he would ever recover.

He would hold himself together for now. As long as anyone needed him, he would be here, ready to help. But after that...he wasn't sure what would happen.

Ronon informed Teyla that they were at the stairs, and heading down them now. Even he sounded a little out of breath. John couldn't even imagine how Carson was faring.

"You must be on the lookout for the Replicator now," Teyla said. "You are very nearly to the lab."

"Stay on comms as much as you can," John said. "We need to know the second it's safe to power life support back up."

Zelenka had come and talk to John a few minutes ago. He had looked anxious and sick, but informed John that as soon as it was safe, he was ready to turn the power back on. Now, he was standing at the ready, waiting for John's signal.

He had also told John he thought everything would stay stable for at least fifteen more minutes. After that, he couldn't promise anything.

John wished he could close his eyes, but he wasn't sure he'd be able to open them again. He hoped that the city could limp along long enough for Ronon to do what he did best. He hoped he wasn't making the wrong choice. He hoped that everything would work out okay, or as okay as it could be at this point. He didn't have anything else to offer but hope, not now.

"You are almost there," Teyla said, her voice growing even more urgent. "Take the next right, and the lab will be at the end of the hallway. We are tracking Elizabeth's subcutaneous transmitter, and the Replicator is very close."

"Got it," Ronon said shortly, putting on an extra burst of speed. Carson followed behind him, breathing heavily, but not giving up. Ronon was impressed.

Ronon rounded the next corner and the lab was in front of him, at the end of a long hallway. His brain struggled to process the information he was getting. At the other end, he was standing in front of the door, Elizabeth draped over his shoulder.

Except it wasn't Ronon, it was a Replicator, and however much it looked like Ronon it was something very different. Ronon hated this thing that had stolen his form, terrorized his friends. His hand tightened around Rodney's weapon and he ran as silently as he could towards his double.

In front of the lab, the fake Ronon swung Elizabeth off his shoulder, letting her slump loosely against the wall. She didn't stir, but Ronon knew she had to be alive. The Replicator must have knocked her out, or drugged her. Just one more reason for Ronon to make it pay.

Ronon pulled out the weapon Rodney had made, closing his fingers around the plasticky handle. He wished that it was a little stronger, something with a weight to it that he could use as a weapon against the Replicator, not just a glorified Taser. But the way it felt now, he'd shatter it with one good hit. It would be mostly hand-to-hand then, at least until Ronon got an opening.

Ronon was three-quarters of the way down the hallway when the Replicator stiffened and turned. Ronon saw his own face harden, probably into the same expression he was wearing now. He - it - stepped away from Elizabeth, leaving her limp against the wall. Ronon didn't have the element of surprise, but at least he wasn't about to enter close combat right above the unconscious leader of Atlantis. Hopefully, Carson would be able to get to Elizabeth while Ronon disposed of the Replicator.

The Replicator broke into a run, and Ronon howled a war cry as they closed the distance. He kicked out at the other Ronon's knee, intending to buckle the joint, drive it to the ground, and hit it with McKay's weapon until it was a pile of metal dust.

He felt the impact as his boot connected, and...nothing happened. Fine, that was fine, Ronon had half-expected that, and he was already moving, using his momentum to work his way closer, stretching his hand out -

A fist smashed into the side of his face, and Ronon suddenly found himself on the ground, blinking stars out of his vision. His own face was looming over him, and Ronon had an unsettling bit of vertigo. This must be how Sheppard felt when they were sparring, peeling himself off the floor while Ronon stood over him, ready to drop him again. Of course, they weren't trying to kill each other then.

Ronon scrambled backwards with one hand, holding the weapon out in front of him in case it tried to get him while he was down. The Replicator at least seemed to realize that the stick Ronon was holding was dangerous, because it allowed Ronon to get to his feet without moving any closer. Ronon shoved his legs under him, still holding the weapon out.

The Replicator advanced again. It threw another punch, but this time, Ronon was expecting it. He ducked under the blow and backed up a step and...his back hit a wall. The last thing he wanted to let the Replicator do was pin him. He ducked under the next strike as he stepped to the side, whirling at the same time. Now, his back was to Elizabeth. He didn't see Carson, so he could only assume he was with her.

He didn't know how much space was between him and his two friends. And however much it was, he didn't like it. He wanted to get the fight farther from them, give himself more space to work with.

Ronon started slowly driving the Replicator backwards with strikes he knew would never land - and wouldn't hurt if they did. The Replicator allowed it to happen. It seemed to be in no hurry. Perhaps it knew that the Nanite Lab did not yet have power, and if he stalled Ronon for long enough, John would have no choice but to power it up.

Ronon parried a punch with his right hand, and, before the Replicator could pull his arm back, he latched onto its wrist. Moving faster than most humans were ever able to, with a speed born from hours of practice, he dragged the Replicator's arm out straight. His left hand locked out its elbow, immobilizing it. Letting Ronon bring him to the ground….

Or at least, that's what Ronon tried to do. He pulled the Replicator's arm out straight before it had time to react. But he had underestimated its pure brute strength. Before Ronon could lock out the Replicator's arm, it had wrenched its wrist free from Ronon's grasp. Ronon gasped as it dragged him off-balance.

Ronon stumbled forward, letting go of the Replicator's arm, barely gaining his footing in time to duck under the thing's next strike. But he hadn't been a Runner for seven years without gaining the skill to show for it, and it was only a half-second before he'd regained his bearings and he rolled up under the Replicator's too-wide strike, ending up inside its guard. With one fluid motion, he pulled Rodney's weapon from where he'd tucked it in the back of the tac vest and jabbed it towards the Replicator's chest.

But it was fast, faster than Ronon would have expected given its nonexistent fighting technique, and Ronon gasped as its hand clamped around his wrist as it came down, stopping the weapon a mere inch from its chest. Its fingers squeezed, tightening, and Ronon gritted his teeth as he felt the thing grind his bones together.

He couldn't withstand the pressure anymore, and his fingers were loosening despite his best efforts. Ronon's hand opened, and the weapon fell - right into his left hand, positioned ready to catch it. Before the Replicator could realize what had happened, Ronon thumbed the switch on the weapon's handle and shoved it into the Replicator's ribs.

There was a spark of blue electricity, and the Replicator showed emotion for the first time. Its eyes - Ronon's eyes - widened in a fear Ronon rarely exhibited. It released his wrist, stumbling backwards, and Ronon saw it shimmer slightly. For a moment, it looked less like him, less solid. Ronon bared his teeth and closed in, pressing the advantage. This didn't need to go on much longer. He'd tasted blood, and he wanted more.

Carson kept a wary eye on the two Ronons as he knelt beside Elizabeth. His preliminary examination had turned up nothing more than a slight contusion on her temple, and although he couldn't get her to rouse, her pupils were responding to light. She had likely been drugged, and she'd have a nasty headache when she woke up, but Carson's worst fears were unfounded.

Carson had briefly considered trying to get Elizabeth away from the Nanite Lab, leaving Ronon to battle the Replicator, but the two Ronons were blocking the turnoff. All Carson could do was watch over Elizabeth and hope that his Ronon was the one that triumphed.

The fight was almost surreal to watch, and Carson thought wryly that there were probably people on Atlantis who would have very much enjoyed it. John and Teyla, certainly, probably many of the Marines. They would have understood what was going on in a way Carson couldn't hope to follow. All that he could glean from the dizzying whirl of limbs was that both Ronons were very fast. The Replicator version seemed to be stronger, and the Ronon he knew seemed to be doing more complicated moves that Carson's mind translated as nothing more than a blur of movement.

Carson had just turned back to Elizabeth, and was trying to take her pulse, when he heard a grunt from Ronon. His head snapped up. Ronon had apparently tried to dodge and missed, and Carson watched as he stumbled sideways. The Replicator pressed this advantage, advancing on Ronon. Carson gasped as its hand snapped out, catching Ronon hard in the chest.

Ronon went flying backwards. He crashed into the wall, crumpling to the ground in a heap.

"Ronon!" Carson yelled without thinking, and immediately clapped a hand over his mouth. As much as he wanted to help, he didn't want to bring the Replicator's attention towards either him or Elizabeth.

The Replicator didn't so much as glance at Carson, and Ronon didn't stir. Carson felt his pulse thundering in his ears. He was so anxious and horrified that he couldn't swallow. He was afraid he would forget how to breathe.

The Replicator advanced on Ronon, apparently preparing to finish him off. But all of a sudden, Ronon wasn't limp anymore. He jackknifed upward with dizzying speed, and tagged the Replicator in the thigh with the weapon. The Replicator blurred slightly, and Carson held his breath, waiting for it to fall apart.

But it didn't. Its form just shimmered slightly before solidifying. Carson cringed against the wall, shielding Elizabeth's body with his own. He was sure that the Replicator was about to take out Ronon. And then turn on them.

But Ronon was prepared. Instead of immediately dying, when the strike with the weapon didn't work, he threw his weight forward and grabbed the Replicator's legs. His weight bore the Replicator to the ground, and in another instant, Ronon had scrambled on top of him.

Carson's breath was coming in harsh gasps now. He didn't know much about fighting, but this...this looked good. Ronon was on top of the Replicator, keeping it pinned to the ground with his knees. He must have the advantage. What could the Replicator do now? Surely Ronon would be able to touch the Replicator with the weapon as many times as he needed to, and end this fight quickly.

That is, assuming the weapon worked as it was intended to. Rodney had said the charge was weak, and it might need to touch the Replicator multiple times. But Carson had seen Rodney as he'd been working on the weapon. He had a lot of faith in the physicist, but Rodney had seemed so weak and sick….

But it seemed like it was working so far, at least Carson could see something happening when Ronon touched the weapon to the Replicator. And now Ronon looked like he was in a position to continue hitting it until it died.

The end of the fight couldn't come soon enough, Carson thought. Ronon was bleeding - a cut had opened above his eye and the blood was running down his face, dripping onto the other Ronon's cheek. Ronon hadn't seemed to notice, but Carson was desperately worried about what other injuries he'd accumulated, ones Carson couldn't see.

Ronon whipped Rodney's weapon forward, but before he'd gotten it anywhere near the Replicator, the other Ronon made some sort of movement, too fast for Carson to follow. He blinked, and all of a sudden the Replicator's hands were on Ronon's face, clawing. Carson saw more blood, and Ronon growled in pain.

"NO," Carson shouted, sure that they were all about to die, for the second time in less than a minute. He couldn't breathe. His chest was tight, his mouth dry, and he sat there frozen as the Replicator grabbed the side of Ronon's face in its hands and began to squeeze.

It was trying to claw Ronon's eye out. It shouldn't have been able to move, Ronon should have had it pinned, but it was far stronger than he was and now Ronon could feel its fingernails shredding his flesh. It wasn't a move Ronon had expected - it had all the sloppy desperation of something Rodney might have tried, but it was backed by a strength and speed that Ronon couldn't hope to match.

Ronon could feel the pressure in his skull building as the thing squeezed his temple, its fingertips digging into the soft skin around his eye. It felt like his head was caught in a vice, and Ronon struggled not to black out as the Replicator's incredible strength forced him slowly backward and upward.

Its grip somehow tightened again, and Ronon choked back a cry as his vision blurred. He was certain at any second that his eye would pop. He realized that his hands were locked uselessly around the Replicator's wrists, struggling to pull them away from his face. It was pointless, the machine was too strong, and Ronon was going to die here and all of Atlantis would fall.

No, if Ronon was going to die he'd take the Replicator with him. Ronon howled his defiance, letting go of the Replicator and clenching Rodney's weapon in his fist. The pressure increased again, and Ronon gritted his teeth and slammed the weapon into the thing's side. He just hoped that he'd have the strength to do it again, if this didn't work.

The other Ronon shimmered again, flickering gunmetal grey. But this time, it didn't ripple back. Its grip weakened, then released, and Ronon was tumbling to the floor in a shower of metal dust.

"Colonel!" Zelenka yelled. "The readings are rising too fast!"

Zelenka had a series of screens set up in front of him, and he was monitoring the slow decline of Atlantis.

Or, it had been a slow decline. Somewhere in the past thirty seconds, the pressure reading had started climbing. Now, the graph was a sharp hill, and he had maybe….

They were out of time. It was a matter of minutes now, maybe seconds. In an instant, Atlantis could be gone and they could all be dead.

John didn't respond.

"Colonel!" Zelenka yelled again. Did he not understand? Nothing Ronon did with the Replicator would help if they all exploded.

"Wait!" John screamed.

"We haven't heard from Ronon yet!" Teyla shouted. "One more minute!"

"We don't have one more minute!"

"Get us one more minute!" John yelled. "Or Elizabeth-"

Zelenka heard the crackle of comms at the same instant John and Teyla did. Then, Carson's breathless voice.

"Ronon's done it. We're okay."

"Zelenka, NOW!" John screamed.

Zelenka didn't need to be told twice. His hands flew across the keypad as he released power to every area of Atlantis. He slammed the final switch up, the one that powered up the Gateroom.

Immediately, the control panel started glowing. He had left most of the power systems in the Gateroom intact, taking down only what was needed to prevent a surge, but now that the power was back in full force, a thousand little lights started glowing, things Zelenka hadn't even realized he'd turned off.

The sound too - Zelenka hadn't realized how much he missed the steady, gentle hum of the city. He hadn't really noticed its absence. But now that it was back….

It was...they had….

He had done it. He had rescued Atlantis from the edge of destruction. He had performed a miracle on the level of Rodney Mckay.

"It...it is done?" Teyla asked tentatively. "We are safe?"

"Yes," Zelenka said. "We're safe now."

The lights were starting to hurt Zelenka's eyes. He closed them quickly, but then was surprised by a wave of dizziness that washed over him. He opened his eyes quickly and grabbed for the control panel in front of him - he needed something to support himself. The multitude of soft, blinking lights were spinning rapidly in front of him, and it was starting to feel like the ground was spinning too.

He reached out for the control panel, but his depth perception was off. His hand plunged into empty space. He staggered forward, and then he felt his legs folding beneath him.

"Zelenka!" John shouted.

Zelenka tried to respond. But instead his knees hit the ground, and everything went black.

A/N - That's it for the plotty part of this fic! As the title of the fic suggests, the city has been saved! I still have two more chapters to post - this fic was long and complex enough that I needed some time to tie up all the loose ends, and of course I would never want to skip out on aftercare scenes for our boys.

Looking ahead, once this fic is done I have a short and sweet Teyla and Ronon-centric sickfic that's all done and ready to post, and after that I have a funny Ronon and John adventure that I'm halfway through writing.