SUSAN: Nothing. Oh Grandfather, I've never told you how angry I was with you, did I? After we defeated the Daleks all those years ago and you left me here. Even though I suppose I thought I knew you'd never come back. All those years, I was cross that you said you would. I thought... I wish he'd just own up to himself that he never goes back, that he always just goes forward. But... well, you proved me wrong, didn't you?

THE DOCTOR: (laughs) Yeah. I did, didn't I?

SUSAN: Oh! Grandfather, you're back! Oh! I didn't think it had worked.