HARKNESS: When I was with the Doctor, I saw more than I could have ever dreamed. And then... we lost each other. I didn't know what happened to him. If he was alive or... if I was ever going to see him again. Hard way to live. Being with the Doctor, you don't get to choose when it stops. Whether you leave her or... she leaves you.

HARKNESS: How many people in the universe get to meet the Doctor, let alone travel with her? We're the lucky ones, Yaz. Enjoy the journey while you're on it. Cos the joy... is worth the pain.

DOCTOR: I don’t want to go.

DOCTOR: I'm the winner. That's who I am. The Time Lord Victorious!

DOCTOR: There are laws of time. Once upon a time there were people in charge of those laws, but they died. They all died. Do you know who that leaves? Me! It's taken me all these years to realize that the laws of time are mine and they will obey me!

DOCTOR: People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint, it's more like a big ball of wibbly-wobbly, timey-wimey... stuff.

DALEK SEC: This is not war – this is pest control!

DOCTOR: The Daleks have failed! Why don't you finish the job and make the Daleks extinct. Rid the Universe of your filth. Why don't you just die?

DALEK: You would make a good Dalek.