She's a breath of fresh air, a reminder of all that is worth looking after in this universe. She reminds him of what his sacrifice (their sacrifice, really, since it is they who are dead and he survived) has saved. The most ancient and powerful race in the universe eradicated so that girls like Rose Tyler can eat chips and text their mates. There is a logic in that somewhere, he is sure, but he hasn't found it yet.

He is so tired of being alone.

There is so much, there in his head. So many thoughts, ideas and sometimes nightmares. He is just longing for someone who can understand. He needs to share some of that horror eating him away inside. He knows that it is selfish and he knows that it is wrong, but perhaps he's just a little bit wrong himself. He thinks that he may have forgotten how to deal with people who are completely right.

So he takes her to the end of her world.

He doesn't even realise why he's doing it at the time, but he needs her to feel some of what is churning away inside of him. He's breaking her, just a little bit, so that they can both be traumatised together. He really doesn't cope very well on his own.

She, in turn, clings desperately to the idea of a hero, the strong male role model she never knew growing up. Unconsciously, they exploit each others' weaknesses with almost frightening ease. He's using her as a distraction from the thoughts and the memories and the ohpleaseno. They both know this, although perhaps they will refuse to admit it, and still cling to each other, fearing that darkness will swallow them if they ever let go.

She wants to see the wonders of the universe so he takes her to a war zone. There is an almost perverse satisfaction in seeing her cry. He grieves though her, and heals through her too. There is an even greater satisfaction in the way that she recovers, still believes in happy endings and trusts him when he tells her that things are going to be okay. He buys into her blind faith because he wishes that he was naïve enough to have some of his own.

It's not healthy, but neither of them really insist that it is. They are two wrongs clinging to each other in the midst of turmoil and anguish, and somehow managing to leave a right in their wake.