"The truth?" Martha's laugh echoes harshly in the stillness of the TARDIS. There's a humourless hollowness to the sound. She hasn't told the Doctor the truth yet - why she's travelling with him, why she isn't engaged anymore, why she finds it hard to sleep even when things aren't horribly wrong. She can't tell him any of it, because he'll just blame himself. It's his fault - but she's not entirely blameless either. And the worst part is, knowing the consequences of her actions, she still isn't sure she'd change anything if she had the chance.

Instead of saying any of that, she sighs and places a hand on his back. She can't leave him alone, can't abandon him. He needs someone. Maybe his punishment for his sins is to be stuck with her. Maybe it's her punishment. She doesn't really know anymore.

"Oh, yeah, obviously the solution is just a bit more elbow grease. 'Cos you just haven't been trying hard enough already." Though her tone is sarcastic, she rubs his back soothingly. He doesn't know how to fix the TARDIS, she doesn't know how to fix him. They're both a bit rubbish at being doctors right now.