Doctor Who: The Crooked World

'You see?' said the Doctor. 'A simple moment of joy. Perhaps you're right, Streaky, these changes might bring anguish, pain and even despair, but isn't it worth it? You have opportunities now. You can live up to your potential. You can be so much more than you were before. Sheriff, you'll listen to me now, won't you?'

The Doctor had stood up and put a fatherly arm around Anji's shoulders.

–but I need you to trust me. –I do. –I mean implicitly. Enough to place your life in my hands. Fitz didn't answer that. He was too busy thinking about the implications of the statement. –When I say run, - said the Doctor, –you take my hand and you close your eyes as tightly as you can, and then you run. –How can I? –Implicitly, Fitz, remember? I'll guide you. But whatever happens, you must keep your eyes shut.