The Doctor: Listen! Question: why do talk out loud when we know we're alone? Conjecture: because we know we're not. Evolution perfects survival skills. There are perfect hunters There is perfect defense. Question: why is there no such thing as perfect hiding? Answer: how would you know? Logically, if evolution were to perfect a creature whose primary skill were to hide from view, how would you know it existed? It could be with us every second and we would never know. How would you detect it? Even sense it? Except in those moments when for no clear reason, you choose to speak aloud. What would such a creature want? What would it do? Well? What would you do?
The Doctor: Why do you have three mirrors? Why don't you just turn your head?
The Doctor: I need you, for a thing.
Clara: I can't.
The Doctor: Oh, of course you can. Come on, you're free. More than usually free, in fact.
Clara: No, it's possible I might get a phone call.
The Doctor: From the date guy? Well, it's too late, you've taken your make-up off.
Clara: No. I haven't. I'm still wearing my make-up.
The Doctor: All right, you probably just missed a bit.
The Doctor: I think everybody at some point in their lives has the exact same nightmare. You wake up, or you think you do, and there's someone in the dark, someone close. Or you think there might be. So you sit up, turn on the light, and the room looks different at night. It ticks, creaks, and breathes. And you tell yourself there's nobody there. Nobody watching, nobody listening, nobody there, naturally. And you very nearly believe it. You really, really try. And then...
Clara: I've never been to Gloucester in my life. And I've never lived in a children's home.
The Doctor: You probably just forgot. Have you seen the size of a human brain? It's hilarious. Little you must be in here somewhere, with your little brain.
The Doctor: Let me tell you about scared. Your heart is beating so hard I can feel it through your hands. There's so much blood and oxygen pumping through your brain, it's like rocket fuel! Right now you could run faster and you can fight harder. You could jump higher then ever in your life. And you are so alert, it's like you can slow down time. What's wrong with scared? Scared is a super-power. It's your super-power. There is danger in this room, and guess what? It's you. Do you feel it? Do you think he feels it? Do you think he's scared? Nah. Loser. Turn your back on him.
The Doctor: The deep and lovely dark. We'd never see the stars without it.
The Doctor: Gone.
Rupert: He took my bedspread.
The Doctor: Ah, the human race. You're never happy, are you?
The Doctor: People don't need to be lied to.
Clara: People don't need to be scared by a big grey-haired stick insect, but here you are. Stay still, shut up.
Clara: Is that what I look like from the back?
The Doctor: It's fine.
Clara: I was thinking it was good.
The Doctor: Really?