DOCTOR: Can't I ever have peace? Can't I rest?

BILL: Of course you can.

NARDOLE: It's your choice.

BILL: Only yours.

NARDOLE: We understand.

DOCTOR: No. No, you don't. You're not even really here. You're just memories, held in glass. Do you know how many of you I could fill? I would shatter you. My testimony would shatter all of you. A life this long, do you understand what it is? It's a battlefield, like this one.

(The Doctor gestures to the desolate battlefield behind him)

DOCTOR: And it's empty. Because everyone else has fallen.