I can't. Even the tiniest change, the ramifications could be catastrophic. It could spread carnage and chaos across the universe like ripples on a pond. Oh, well, I've had a good innings. This regeneration, it's a bit of a clerical error anyway. I've got to go sometime.
CClara
Not with me! Die with whoever comes after me. You do not leave me.
I can't change what's already happened. There are rules.
CClara
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. 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.
Immortality isn't living forever, that's not what it feels like. Immortality is everyone else dying. She might meet someone she can't bear to lose. That happens… I believe.
To die? They wouldn't thank you for that. Nor you, Clara. "To die, to die, Glamis hath murdered sleep, therefore Cawdor shall sleep no more. Macbeth shall sleep no more."
Shakespeare. He really knew his stuff. They all did: The ancients, the poets. All those sad songs, all those lullabies. Sleep is essential to every sentient being in the universe. But to humans — greedy, filthy, stupid humans? It's an inconvenience… to be bartered away!
Yes, it is. You can, and you will, or this street will be over. I'll show you and all your funny little friends to the whole laughing world. I'll bring UNIT, I'll bring the Zygons - give me a minute, I’ll bring the Daleks and the Cybermen. You will save Clara, and you will do it now, or I will rain hell on you for the rest of time!
I can do whatever the hell I like. You read the stories, you know who I am! And in all that time, did you ever hear anything about anyone who stopped me?
[to the Doctor] You. You listen to me. You're going to be alone now, and you're very bad at that. You're going to be furious, and you're going to be sad, but listen to me. Don't let this change you. No, listen. Whatever happens next, wherever she is sending you, I know what you're capable of. You don't be a warrior. Promise me. Be a Doctor.
What's the point of being a Doctor if I can't cure you?
CClara
Heal yourself. You have to. You can't let this turn you into a monster. So, I'm not asking you for a promise. I'm giving you an order. You will not insult my memory. There will be no revenge. I will die, and no one else, here or anywhere, will suffer.
The universe is over! It doesn't have a say any more! We're standing on the last ember, the last fragment of everything that ever was. As of this moment, I'm answerable to no-one!