Before the Flood

DOCTOR: I can't change what's already happened. There are rules.

CLARA: So break them. And anyway, you owe me. You've made yourself essential to me. You've given me something else to, to be. And you can't do that and then die. It's not fair.

DOCTOR: Clara.

CLARA: No. Doctor, I don't care about your rules or your bloody survivor's guilt. If you love me in any way, you'll come back. Doctor, are you?

BENNETT: Yeah. Yeah. Except now you're going to do something about it, aren't you? Yeah, because it's getting closer to you. You change history to save yourself but not to save O'Donnell. You wouldn't save her.

DOCTOR: This isn't about saving me. I'm a dead man walking. I'm changing history to save Clara.

FISHER KING: You will be a strong beacon. How many ghosts can I make of you?

DOCTOR: You know, you've got a lot in common with the Tivoleans. You'll both do anything to survive. They'll surrender to anyone. You will hijack other people's souls and turn them into electromagnetic projections. That will to endure. That refusal to ever cease. It's extraordinary. And it makes a fella think. Because you know what? If all I have to do to survive is tweak the future a bit, what's stopping me? Oh, yeah, yeah, yeah, yeah, yeah. The ripple effect. Maybe it will mean that the universe will be ruled by cats or something, in the future. But the way I see it, even a ghastly future is better than no future at all. You robbed those people of their deaths, made them nothing more than a message in a bottle. You violated something more important than Time. You bent the rules of life and death. So I am putting things straight. Here, now, this is where your story ends.