Bonnie: Why are you doing this?
Kate: Yes, I'd like to know that too. You set this up -- why?
The Doctor: Because it's not a game, Kate. This is a scale model of war. Every war ever fought right there in front of you. Because it's always the same. When you fire that first shot, no matter how right you feel, you have no idea who's going to die. You don't know who's children are going to scream and burn. How many hearts will be broken! How many lives shattered! How much blood will spill until everybody does what they're always going to have to do from the very beginning -- sit down and talk! Listen to me, listen. I just -- I just want you to think. Do you know what thinking is? It's just a fancy word for changing your mind.
Bonnie: I will not change my mind.
The Doctor: Then you will die stupid. Alternatively, you could step away from that box. You could walk right out of that door, and you could stand your revolution down.
Bonnie: No, I'm not stopping this, Doctor. I started it. I will not stop it. You think they'll let me go after what I've done?
The Doctor: You're all the same, you screaming kids, you know that? "Look at me, I'm unforgivable." Well here's the unforeseeable, I forgive you. After all you've done. I forgive you.
Bonnie: You don't understand. You will never understand.
The Doctor: I don't understand? Are you kidding? Me? Of course I understand. I mean, do you call this a war, this funny little thing? This is not a war. I fought in a bigger war than you will ever know. I did worse things than you could ever imagine, and when I close my eyes... I hear more screams than anyone could ever be able to count! And do you know what you do with all that pain? Shall I tell you where you put it? You hold it tight... Til it burns your hand. And you say this -- no one else will ever have to live like this. No one else will ever have to feel this pain. Not on my watch.
[Kate closes her box.]
The Doctor: Thank you. Thank you.
Kate: I'm sorry.
The Doctor: I know. I know, thank you.