CHARLEY (reading the letter): Dear Doctor, it's been such a long journey for both of us. I never ever wanted it to end, but end it has, we both know that.

DOCTOR: Oh, Charley, no.

CHARLEY (reading the letter): A long time ago now I said you were the oddest man I'd ever met. You are that still. You are the best man I've ever met too. But we've chanced our luck once too often I think, so I'm bailing out. Escape strategy number Five.

DOCTOR: Number Six!

CHARLEY (reading the letter): I'm going to disappear. There's no freedom like being dead. I can go anywhere, be anyone I want. Just like a Timelord really... Don't look for me, please. But remember me. I'll remember you, always. With love, the girl who never was.