"To hell with that, I am not leaving you!" Jack yelled.

"I really don't have the time to argue with you Jack!" the Doctor snapped back, acutely aware of the wailing alarm.

They were carrying a semi-conscious Gwen down the corridor towards another set of doors.

The Doctor had handed the sonic to Ianto. "Open the door with this," he'd said ignoring the glare he got from Jack. In his mind he could hear the TARDIS.

'He is worried, he sees this as suicide, he does not understand.'

'I know, but I cannot blame him. To get me back and then thinking he's losing me again.'

'He will understand'

'Perhaps, have you found Martha Jones yet?'

'She is below us, she is unguarded.'

'Show me where?'

An image of Martha in an unlocked room flashed through his mind, and then an image of the shuttle bay followed.

'She is there, next to the shuttle bay. They can escape.'

'Good, then I will finish this, the Chaos cannot be allowed to live.'

'There is no other way...sacrifice'

The Doctor said nothing in reply but spoke instead. "Martha's on the next level. There's a room next to the shuttle bay, it's unlocked, she's in there."

Ianto opened the door and handed the sonic back to the Doctor and helped Jack with Gwen into what was an elevator.

Jack had just about got inside the elevator when the door began to shut. He turned and saw the Doctor pointing the sonic at the door, a look that said a thousand words on his face.

"No!" Jack cried and moved, but the door slammed in his face.

The Doctor looked at the closed door, his hearts aching with the guilt at the hurt he was causing...once again. He felt the tickle of the TARDIS in his mind.

'It is time,' the TARDIS said.

White Coat strode down the corridor, a group of guards behind him.

"When you find my property, shoot to disable, not to kill. As for the others, shoot to kill."

"Yes sir!" they chorused and split off into pairs.

White Coat smiled, this time his property would not escape, even if he had to make sure it never walked again.

Jack pounded on the door of the elevator as he felt it go down. "No, no, no, bring this thing back up!"

"Don't bother, I don't think he's listening," Ianto said. "We have to find Martha and get out of here. I think he's going to do something...explosive."

Jack whirled round, his face full of anger. "You'd like that, wouldn't you," he snarled. "You've always been jealous of him. You can't stand the fact that I can't love you like I do him."

Ianto didn't react to the words, knowing that he was hurting and lashing out at the nearest person.

"Jack, he did this because he loves you. Don't make him regret it. We have to take Gwen and Martha and find somewhere safe until this is over."

Jack scowled at Ianto but said nothing as the elevator pinged and opened. Oh, he'd find Martha, but there was no way he was going to let the Doctor commit suicide. He'd waited too long and gone through too much to let the Doctor slip away from him again.

As the door opened he let Ianto carry Gwen through first and then pushed the close button.

Ianto didn't turn, knowing what Jack was going to do.

"Bye Jack," he said and placing Gwen gently on the floor, he walked towards the smallest door in the corridor.

The Doctor stood for a few moments, listening to the sound of the elevator moving. He knew Jack would be climbing the walls to get out. He took in a deep breath, blinked and shook himself...time to move.

'You must hurry, the Chaos is approaching Earth' the TARDIS reminded him.

'Yes, yes, but I go to get to the chamber first. I need that weapon.'

Steven James couldn't see the point in running, that thing, whatever it was, it was big enough to swallow the Earth whole. He looked through the lens again and frowned, had the black mass stopped? Yes it had, it seemed to motionless, like it was waiting, but waiting for what?

He would have phoned someone, but who could he have phoned, there was no-one there to answer.

He looked again, yes it was definitely not moving, it looked like a predator waiting for its prey to move closer. Why was it waiting?

White Coat strode along the corridor, two of his guards behind him. He was heading towards the chamber, something told him that was where his property was heading. He knew his property had the key, but would he know how to use it.

He really needed to get there before he tried.

The Doctor hurried along the corridor, his target only a few feet away now. He could feel the human DNA trying to mix with his own. He knew he couldn't let it stay inside him for long, his body would soon reject it and it would be useless.

"Door, door, which door?" he said to himself as he was faced with three doors. "If I could only remember."

He let out a frustrated breath, why couldn't he remember. "This isn't fair!" he cried.

"Life rarely is," a voice said behind him.

He whipped round and there was his nemesis, a smug smile on his face and two guard with weapons aimed at him.

White Coat smiled as he saw his property startled expression.

"Did you really think it would that easy to gain access. You may have the key, but you don't know which door it fits. A clever idea don't you think, using Miss Cooper's DNA. I assume you've ingested it, so your time is limited, your body will start rejecting it soon. Oh don't look so surprised, I know how your body works almost as well as you do. Now come away from the doors and you can take your rightful place."

Anger took over from the Doctor's surprise. "What, as your prize pet? I don't think so. I think the answer is behind door two!" he yelled and dived, hand outstretched.

"No!" White Coat shouted as the Doctor's hand thumped on the panel by the second door, and rushed forward as the Doctor turned the dive into a perfectly executed Arabic and landed

"No!" White Coat shouted once again and sprinted towards the open door, squeezing through, just before it slammed shut.

"Doors sealed, automatic emergency ejection in progress," a voice rang out.

White Coat steady himself as the whole chamber shuddered...the weapon, it was moving.

"Looks like it's just you and me then," the Doctor said and stepped away from the control panel.

White Coat looked out of the small observation window, then at his property in horror. "What have you done!"

"Atoning for my sins and yours," the Doctor said.