Lunn: Are you sure the Doctor won't just leave us here?
Clara: Guys look, this is how we roll. He's gonna go away, come back and we'll have to listen to how he did it.

The Doctor: Tell me, what about those things out there? What are they? Why are they trying to kill us?
Bennett: Well, they're... they're ghosts.
The Doctor: They're not ghosts.

So we are fighting an unknown homicidal force - that has taken the form of your commanding officer and a cowardly alien - underwater, in a nuclear reactor. Anything else I should know?

The Doctor

Wait a minute, you know what this means? It means that they're not a natural phenomena. It means that someone is deliberately getting people killed, hijacking their souls and turning them into transmitters.

The Doctor

I want another adventure. Come on, you feel the same. You're itching to save a planet. I know it.

Clara

The Doctor: They're ghosts! Yeah, ghosts.
Clara: You said there was no such thing. You actually poo-pooed the ghost theory.

Bennett: Wait, you're going to go back in time? How do you do that?
The Doctor: Extremely well.

We are fighting an unknown homicidal force, underwater, in a nuclear reactor.

The Doctor

Doctor Who Season 9 Episode 3 Quotes

The Doctor: Tell me, what about those things out there? What are they? Why are they trying to kill us?
Bennett: Well, they're... they're ghosts.
The Doctor: They're not ghosts.

We are fighting an unknown homicidal force, underwater, in a nuclear reactor.

The Doctor