- Bill: Why do you put up with us, then?
- The Doctor: In amongst seven billion, there's someone like you. That's why I put up with the REST of them.
- Missy: [in tears] You remember all the people I've killed? Every day, I think of them all. Being bad... being bad. I didn't know I even knew their names. You didn't tell me about this bit.
- The Doctor: I'm sorry. But this is good.
- The Doctor: Human society is... stagnating. You've stopped moving forward. In fact, you're regressing.
- Bill: Well, this isn't exactly much better.
- The Doctor: It's safer.
- Bill: Not so much for the people the Monks are killing.
- The Doctor: The Romans killed people and saved billions more from disease, war, famine, and barbarism.
- Bill: No, wait. What about free will? You believe in free will. Your whole thing is... You made me write a 3000-word essay on free will!
- The Doctor: Yes, well, you had free will, and look at what you did with it. Worse than that, you had history. History was saying to you, "Look, I've got some examples of fascism here for you to look at. No? Fundamentalism? No? Oh. Okay. You carry on." I had to stop you, or at least not stand in the way of someone else who wanted to. Because the guns were getting bigger, the stakes were getting higher, and any minute now, it's gonna be "Goodnight, Vienna". By the way, you never delivered that essay.
- Bill: Because the world was invaded by zombie monks!
- The Doctor: Humanity's doomed to never learn from its mistakes.
- Bill: Well... I guess that's part of our charm.
- The Doctor: No. It's really quite annoying.
- Missy: You know, back in the day, I burned an entire city to the ground just to see the pretty shapes the smoke made. I'm sorry your Plus One doesn't get a happy ending. But like it or not, I just saved this world because I WANT to change. Your version of "good" is not absolute. It's vain and arrogant and sentimental. If you're waiting for me to become all that, I'm going to be here for a long time yet.
- Bill: [upon entering the vault and seeing Missy] It's... it's just a woman. God, the way you and Nardole have been carrying on, I thought you had some kind of monster in here or something.
- The Doctor: I do.