Graham and The Doctor in “The Battle of Ranskoor Av Kolos”

I need to be honest with you, because I am really grateful for everything you've done for me. Well, for us, you know. Everywhere we've been, all the adventures. Been amazing. But if that is the creature from Sheffield, I will kill it, if I can, for what it did to Grace.

Go back to the TARDIS, Graham.

Nah.

I won't let you do that.

You ain't gonna have a say in it.

You're better than this. You are. You have to be. If you kill him, I can't have you travel with me. That's if you even live.

I understand.

No, you don't. We're gonna rescue hostages. Anything that compromises them is dangerous. And if you kill him, you become the same as him.