Jack turned his head and glanced at the door, worried about the world that sat behind it. Earth, 'home', so much more scary in so many ways than any alien planet.

"No," Jack agreed, glancing down again, feeling guilty for having said it, "no, it's not. But I'll fix it. I'll fix things this time. I'll do it right."

The Doctor was right, Martha wouldn't be far away, so Jack had to go. He had to go now. Do it quick, like pulling off a plaster. Quick and sharp.

He turned as if to move to the door, but stopped again and turned back. "Three weeks," he said again, "three weeks, and I'll meet you here. And if you need me too, Doctor, you call me, okay? You know where I am."

Repeating his movement he made for the door, a couple more steps before again stopping and turning back, this time striding the few steps back to the Doctor. He approached him quickly and without questioning or speaking at all, he kissed him. Just one kiss, brief but with pressure behind it, before pulling back and nodding.

"See you soon, Doctor."

And with a tight smile, he turned and left the TARDIS.