DOCTOR: Do you know like we were saying about the Earth revolving? It's like when you were a kid. The first time they tell you the world's turning and you just can't quite believe it because everything looks like it's standing still. I can feel it. The turn of the Earth. The ground beneath our feet is spinning at a thousand miles an hour, and the entire planet is hurtling round the sun at sixty seven thousand miles an hour, and I can feel it. We're falling through space, you and me, clinging to the skin of this tiny little world, and if we let go. That's who I am. Now, forget me, Rose Tyler. Go home.

'He can take care of himself,' Fitz muttered, starting for the kitchen. He always had, after all, for hundreds of years. Still, at some point his luck was bound to run out. But please not today, Fitz thought, as he grasped the pantry door handle. Please never, as long as I'm with him.

TEGAN: You believe him because he gave up Enlightenment for your sake.

DOCTOR: You're missing the point. Enlightenment was not the diamond. Enlightenment was the choice.