My apologies for the delay in posting - darned real life. And thank you to everyone who reviewed! They are always most appreciated.

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Mikey stared at the woman aiming casually at them. "Layla? What the hell are you doing?"

"Sorry Mikey," she said unrepentantly. "But I'm not really a rookie. Bishop wanted me to keep an eye on you."

"On me?" Mikey looked completely confused. "But why?"

"Well, not just on you. There's been someone around all of you, reporting back to him, just in case something like this happened."

"Let me guess," snarled Raph. "Bishop had his spies all over the place, making sure we didn't step outta line, decide we'd had enough of his bullshit."

"Pretty much," said Layla, never relaxing her guard. "Been getting reports about all of you since you were kids. He's always been prepared for something like this. Personally, I'm surprised you waited this long to make a break for it. Now drop your weapons before I ventilate your shells."

Raph curled his lip for a moment, wondering if there was any way they could disarm her before she could fire at them – then, realising it was unlikely without at least one of them getting hit, threw down the tranquilliser gun, pulled out his gun and tossed that aside too. But he made sure they landed on the ledge above the water. If there was any chance he could get to them, he wanted the weapons to be in working order and not wet and ruined. Don and Mikey followed his example, Mikey taking the longest time with his extensive stash of explosives. Raph just hoped he hadn't given up all of them.

"Smart," said Layla. "Now, we're gonna go back to Bishop and you'll be taken back to the base. One wrong move and I blow a hole through whichever one of you's nearest. Get it?"

"We get it," snapped Raph, furious that she got the drop on them in the first place.

"That creature's still in the tunnels somewhere Layla!" said Mikey urgently.

Layla gave a one-shouldered shrug. "I pumped enough bullets into it. Has to be dying. The rest of the team are gonna bring it down while I take care of you freaks."

"It already brought down one of the teams," pointed out Don.

"They got careless. Start walking. And put your hands where I can see 'em."

Raph turned toward the tunnel leading to the exit, hands raised. He hated to turn his back on his enemy, it made him edgy when he couldn't see where the gun was pointed, but it was a relief to not have to look at her any more, the expression of calm, almost remorseful efficiency. "So, how many people has Bishop had working for him?"

"A few. He doubted that you three could be trusted. Looks like he was right."

"So why were we brought up like we were instead of as test subjects?"

"Agent Bishop has his superiors too and they chose not to listen to him when he suggested that. But as you were about to go AWOL and destroy Government property, I guess they'll change their minds."

"Government property being that poor creature out there?"

"Yes. You three are Government property too. It's not up to you what happens to you."

"We're basically test subjects," said Don, uncharacteristically bitter, his eyes firmly forward as they walked. "They wanted to see our potential, if we could be integrated and taught. And they could take samples from us too. We always knew it, that's why we've never been allowed from the base at the same time without a whole bunch of other agents. Well, not before today and the circumstances were a little – unusual."

"And what happens to us now?"Mikey asked.

"I don't know," replied Layla. "And frankly, I really don't..."

Her voice cut off as a loud crash sounded behind the four of them. The three turtles turned, ignoring the previous warnings. Layla spun around, both guns blazing. Gunshot echoed throughout the tunnel, the flashes from the guns illuminating the scene in nightmarish bursts.

The creature was right behind them.

Layla's bullets hit it in the torso and she yelled defiantly as they connected, sure of her triumph. The turtles, unarmed, could only watch...

Almost unarmed. Mikey had been waiting for the opportunity to use some of the smaller devices he had stashed away, having managed to discard only the obvious weapons.

The creature shrieked, the force of the bullets forcing it back – and then it swung a powerful arm, catching Layla's right hand and knocking the gun in it aside, throwing off her balance so the gun in her left missed it, the bullets taking a chunk from the tunnel wall instead.

And then it grabbed her by the right upper arm, gripping the flesh cruelly tight, pulling her toward it.

Layla screamed in alarm, bringing her gun around to put a bullet in its brain – but it swatted the hand as casually as a person might swat at a fly, the gun flying out of sight, the unimportant cracking sounds suggesting a couple of the bones had broken.

Mikey ignited the grenade he had been hiding, small enough to stash unseen, sophisticated enough to release a short but powerful blast...

"FIRE IN THE HOLE!"

Raph and Donnie both dived for cover, Mikey standing his ground long enough to hurl the device at the creature before following suit.

Oblivious to the danger it was in, the creature pulled Layla closer to it, snarling in her face, tightening its grip so that the snapping of her bones was clearly audible over the sound of her screams...

The grenade exploded.

The flash was bright enough that the turtles could see it light up the tunnel through their closed eyes and defensive postures. Sewer water kicked up in the air, showering everyone with foul smelling gunk. Layla's screams abruptly cut off, but the creature's more than made up for it, the volume almost deafening them all, the echoes making the noise seem even louder, assaulting them from all sides.

And within seconds, the grenade had burned itself out, plunging the tunnel back into darkness and leaving only the tortured shrieks of the creature.

Raph went for his infra red goggles, which were still perched on the top of his head, then decided there was little point and snatched for his torch instead, which Layla hadn't insisted they discard, flipping it on and aiming the light in the direction of the creature.

It threw Layla's limp form aside, turning from the light and stumbling back the way it had come, in the direction of their weapons. It continued to roar, almost falling and leaning a hand on the wall of the tunnel to regain its balance. It was trying to get away.

Raph darted to where it had grabbed Layla and searched the area for her guns. At first he saw nothing, then the torch light glinted off something metallic below the dirty water and Raph grabbed at it, finding one of the guns and lifting it, wondering if he could finish it all now with one well aimed shot...

The gun didn't fire, too wet to be operative.

Before he could tell Mikey to pull his finger out of his ass and find another one of those nifty grenades, the creature was almost back to the fork in the tunnels, still having some troubles walking, evidently in pain. By the time they managed anything, they would have lost it for sure.

But at least they could grab their guns now and go after it. They'd barely made it a few hundred yards from the place they discarded their weapons and there was no one to stop them anymore.

As if reading his thoughts, Mikey hurried over to Layla, who was lying face down in four inches of sewer water. Raph reflected that if she was still alive, she was gonna have some serious gastric issues over the next few days.

The creature disappeared down the tunnel running left. Raph allowed himself to turn his attention to his brothers. Donatello was heading over to where Mikey was attempting to find some sign of life in his treacherous protege.

His eyes met Donnie's as he approached, the scientist telling him everything he needed to know in one look.

"I killed her." Mikey's voice was low and filled with horror.

Raph was about to dispute the claim when he took a good look at the corpse and rethought. The woman had taken some serious damage from the creature true, both arms twisted at a weird angle where it had shattered the bones, deep wounds where its claw like hands had broken the skin... but those things alone were survivable. What most likely caused her death was the damage to her face and neck, the charred, melted skin on the left side of her face and the raw blisters on the right. The flesh of her neck, above the plain black T-shirt and bulletproof vest, had split in several places. Blood was flowing from her wounds but slowly, the way it did when the heart was no longer pumping it around the body.

"I just threw the grenade," continued Mikey, oblivious to Don and Raph, talking more to himself than them. "I didn't even think about her... I just saw my chance..."

"Hey Mike," said Raph, resting his hand on his brothers shell. "That thing woulda killed her anyway. You did what you had to and you probably saved our shells."

"And I don't think these would have been immediately fatal," added Don, examining the injuries. "I imagine it was a heart attack brought on by the situation. It happens at times, even in younger people and she was just about to be torn limb from limb."

"And she was blown halfway to hell," added Mikey.

"I doubt it helped matters," said Don truthfully. "But if you hadn't done that, the creature would have killed her or else we would be half way back to the base by now to experience being on the wrong side of the cage."

"Speaking of which." Raph hurried over to where they had discarded their weapons and retrieved them. "We need to go after it, stop it. No matter what else we do now, we can't let that thing wander around like it is. It could hurt someone."

"And if Bishop catches it, he'll use it to further his research," said Don, obviously still angered that he had more to do with the creatures existence than he would have liked.

Mikey nodded, leaving Layla's corpse where it was. "Let's go. I've got enough blast to incinerate it so Bishop can't retrieve a single cell."

"Put the poor damn thing out of it's misery," agreed Don.

Raph shoved his gun in his belt. "Let's go."

&&&&&&&&&&&&&&

There was pain.

Even before he realised he was changing, there had been pain, which had risen as time passed. The change had brought with it a terrible buzzing in his head that served to anger him more, the memories of his time in the labs running through his mind. It was as if the floodgates had been opened. He couldn't control his fury any more.

He couldn't even begin to try, not with the unceasing sounds in his head and the agony that flared through his bones as they elongated, the terrible cramping of his muscles as they grew. A part of him, the part of him that was still capable of thought, was dimly afraid that by breaking through the bars of the cage there would be PUNISHMENT... but they had to catch him first. They had hit him with little pellets that left scratches across his skin, irritating him, fuelling his rage. and for the first time, there was something he could do about it.

How he got out of the building was mostly a blur. He had thrown aside everyone who got in his way, trying to get away, no though or concept toward revenge. He wanted to go somewhere to heal, to wait for the pain to go away. But people kept getting in his way, giving him targets for his anger.

There had been men everywhere and then a terrible roaring sound had drilled into his head, followed by hot agony in his side – but the noise and the burning had covered his escape. He had found a place to hide, to heal, to recover from whatever had been done to him...

And they had followed him.

The first ones had merely shot at him in startled reflex, not the scratching pellets but something sharp. One had missed, another bounced harmlessly off his thickened plastron. The third had penetrated his arm and stayed there until he yanked it out, crushing it and rushing into the men, slamming them aside, picking them up and ensuring they would never be able to hurt him again. But whatever had embedded into his arm had made his head feel swimmy, increasing the buzzing in his ears, making his vision dark and his reflexes even slower.

And then other men had come, one with the weapon that released the stinging pellets – but none of them attacked him and he backed off. He had seen them before, with the other men, but they didn't look like men. They looked – familiar somehow. Maybe he should know why, but some abstract concepts, such as memory and recognition, were becoming too difficult for him to focus on. There was pain. There was anger. And there was the terrible confusion beneath it all. He didn't know why he was being chased. There was some vague idea of PUNISHMENT – but even that was becoming dim, an echo of fear that he couldn't put a face to.

And there were still more of them, everywhere. Another – man, although he couldn't really tell the difference – had invaded his sanctuary and he struck before he could be seen, his instincts warning him that he was under threat...

And then, the pain again, a hundred times more intense than before, the same dancing lights on his body, eating his skin.

The pain was too much.

He retreated, not knowing what else to do, expecting the strange men to come after him, finish him off. But they didn't. He wanted to flee but the best he could do was stumble away, in agony where the lights had hit him, bleeding from a number of scratches inflicted upon him, the dart that had hit him making him dizzy. And the noises in his ears increased, making him want to lash out at whatever was tormenting him so. But he couldn't see what made the noise.

He made it as far as he could before giving up, leaning against the tunnel wall and sliding down it, sitting, trying to regain his strength. Once or twice he batted at the air, hoping to chase away whatever was making the noise that hurt his head, but his fists connected with nothing.

For an unknown amount of time, he rested. The side of his face and neck where the light had exploded gave him the most pain and distracted him from the rest of his wounds, but several of them made themselves known from time to time, particularly his arm. As the minutes passed he began to think about moving on, hiding somewhere else, his instincts telling him that he was too exposed in this place and he needed to get away...

And over the buzzing in his ears, he heard the sound of someone approaching, trying to be quiet but not quiet enough. They would find him. And then they would kill him.

There was only one thing left to do.

He got to his feet and prepared to fight for his life.

&&&&&&&&&&&&

There was no talk between the three turtles and no discussion of what came next. They were going after the creature. If they survived, they could make a plan. For the moment, survival was the only thing on their minds. The rest could wait.

Raphael led the way, a gun in either hand, prepared for the creature to attack.

Michelangelo was right behind him, having retrieved his own weapons, debating what was the best course of action to take – in an enclosed space, an explosive charge could do an equal amount of damage to them as it would the target.

This is why I hate going out in the field. One wrong choice and it all goes to hell.

Donatello was armed with guns similar to the ones his brother had, but he had also snagged the tranquilliser gun, hoping that it might be enough to take the creature down should the bullets fail. He was a pretty good shot, but he'd put money on Raph to hit the thing before he even had the chance. Whether that hit put it down though – that was another matter.

The creature had gone some distance but it had left a trail that wasn't too hard to follow – the tunnels showed obvious signs of having been used very recently and it seemed unlikely that the other teams had gotten this far.

Raph suddenly frowned as he recalled there were two guys unaccounted for, the rest of Layla's team. Had they been killed by the creature? Had she sent them back to the surface while she chased down the turtles? Or were they still wandering the tunnels somewhere?

No point in worrying about it. There wasn't a lot he could do.

And then there was a noise ahead of them, splashing water. It could have been a rat or maybe even one of the missing agents, but he knew it wasn't. It was too loud.

Donatello focused the torch ahead of them, all of them having decided against the infra red goggles as they had been little help previously. The creature was there, walking slowly but purposefully toward them. With clinical detachment, Don was able to better take in what he had noticed first about the creature and more besides. He had been right about the height difference between them and it, also about the musculature growth. But what really gave him pause wasn't the differences between the creature and the three turtles.

It was the similarities.

The shell resembled theirs, larger and seemingly thicker but with markings exactly like those he saw on his brothers backs daily. It had a plastron as they did, which had increased in size in accordance to the creatures change and seemed to offer more protection than their own – shots that would have cracked their chest plates had barely even scarred its own – but was in identical proportions to theirs.

Assuming it originally came into contact with a mutagen synthesised from us before it was turned into – this – it must be close to our age judging by its size, definitely the same species, probably done to make sure the mutagen was stable before trying to cross-mutate.

Raphael raised his gun, getting the creature in his sights, going for a head shot. Damn, that thing must be tough. Even if the bullets couldn't get through its shell or plastron, there's enough chunks from its arms and legs for a normal mutant turtle to bleed out. Heals up fast, just like the one at the base, but I'll bet a couple of bullets to the brain close its eyes for good.

The creature roared, throwing its head back in a display intended to intimidate...

Raph's bullet hit it under the chin, shattering the jaw and turning the bellow into a muffled squeal of pain. It staggered backward, claw-like hands flying to the wound.

And still it stayed standing, shrieking loudly, the echoes making Mikey and Don wince.

"Put it down Raph," said Mikey, his voice barely audible over the noise. "Just... please put it out of its pain."

Raph had been blanking out the screams, but he heard Mikey's words and nodded briefly, taking a couple of seconds to aim before squeezing the trigger again.

Blood flew out of the side of the creatures head, silencing its screams. It fell backward, hitting the ground with a crash, throwing up filthy water that was tinged with its blood.

Mikey kept his fingers resting on one of the flash grenades that had wounded the creature in the first place. "Is it – dead?"

"I'm not sure." Don took a few steps forward to examine the creature, but Raph took a hand of his gun momentarily, holding it up briefly in a gesture of cessation before returning its grip to the gun, lowering it very slightly but keeping it at the ready.

"Let's make sure before we take any chances," he said, talking a few steps forward, never taking his eyes from the creature lying in the tunnel...

The creature moved slightly, flexing its hand and letting out a quiet, piteous noise in the back of its throat.

"Crap!" Raph jerked his gun higher again, keeping it aimed at the creature.

"What is it, the Turtle-nator or something?" asked Mikey.

"No." Don raised his own gun, clearly not about to risk being wrong, steeping cautiously forward and getting a closer look at the mutant.

It was still alive, as hardy as the first creature they had encountered – but in terrible shape. Not only had the bullets Raph fired into it caused serious trauma, but the wounds inflicted on it before the encounter had taken a toll also. Don doubted very much that they would have been able to get close enough to it to inflict enough damage to take it down had it not already been weakened, the same way that the other one had been weakened. That one had lived, but this one, that might once have been a mutant turtle just like they were, had been through worse.

It opened red-rimmed, muddy eyes and looked at him. Don saw no anger in the gaze, just incomprehension and pain.

"It's not getting up," he reported to the others, lowering his gun.

Mikey stepped up behind him and gazed on the creature. "So... what do we do now?"

"The only thing we can do. What we came here for." Raphael joined his brothers and aimed his gun.

The creatures bleary gaze met Raphael's and he held it for a moment before refocusing on the shot.

A second later, a bullet went through the creatures eye, the orbital bone breaking under the pressure, a gout of blood mixed with white fluid erupting from the wound and spilling down its cheek as the bullet made its way through the skulls tissues and lodged within the creatures brain.

For a long time none of the turtles moved, staring at the thing, just waiting for it to move, show some sign of life – but there was nothing.