The Doctor: We need a backup in case they don't reach the auxiliary engines in time. Come on, think! Resources! What have we got?
Martha: (over intercom) Doctor?
The Doctor: What is it now?
Martha: Who had the most number ones: Elvis or the Beatles? That's pre-download.
The Doctor: Elvis. No! The Beatles. No! Wait, um... um... oh, there was that remix, um... I don't know! I am a bit busy.
Martha: Fine, I'll ask someone else.
The Doctor: Now, where was I? Here Comes The Sun. No, resources!
(trying to open a password-sealed door)
Riley: Find the next number in the sequence: 313, 331, 367... what?
Martha: You said the crew knew all the answers!
Riley: The crew's changed since we set the questions.
Martha: You're joking.
The Doctor: 379.
The Doctor: It's a sequence of happy primes. 379.
Martha: Happy what?
The Doctor: Just enter it!
Riley: Are you sure? We only get one chance.
The Doctor: Any number that reduces to 1 when you take the sum of the square of its digits and continually reiterate until it yields 1 is a happy number, any number that doesn't isn't, a happy prime is a number that's both happy and prime, now type it in! I don't know, talk about dumbing down. Don't they teach recreational mathematics anymore?
(After speaking to Martha, Francine hands the mobile phone to a blonde woman who seals it in a bag)
Francine: That's all?
Sinister Woman: For now. Have you voted?
Francine: Of course. Just don't expect me to tell you who for.
Sinister Woman: Thanks for all you're doing, Mrs. Jones. Mr. Saxon will be very grateful.
Martha: (saying goodbye to Riley) It was nice, not dying with you. I reckon you'll find someone worth believing in.
Riley: I think I already did.
(after a pause, the two of them kiss)
Scannell: (seeing the TARDIS) This is never your ship.
The Doctor: Compact, eh, and- another good word- robust. Barely a scorch mark on her.
The Doctor: It's your fault, Captain McDonnell.
McDonnell: Riley, get down to Area 10 and help Scannell with the doors. Go!
(Riley heads off)
The Doctor: You mined that sun, stripped its surface for cheap fuel. You should have scanned for life!
McDonnell: I don't understand.
Martha: Doctor, what are you talking about?
The Doctor: That sun's alive, a living organism. They scooped out its heart, used it for fuel and now it's screaming!
McDonnell: What do you mean? How can a sun be alive? Why is he saying that?
The Doctor: Because it's living in me.
McDonnell: Oh my God.
The Doctor: Humans! You grab whatever's nearest and bleed it dry. You should have scanned!
(Martha phones her mother to say goodbye)
Martha: Mum… you know I love you, don't you?
Francine: Of course I do. What's brought this on?
Martha: I never say it. Never get the time or never think of it and then... (starts to cry) I really love you. Tell Dad, Leo and Tish that I love them too.
Francine: Martha, what's wrong?
Martha: Nothing, I promise.
Francine: Where are you?
Martha: Just out.
Francine: With anyone nice?
Martha: Some mates.
Francine: What mates?
Martha: Mum, can we not just talk?
Francine: Of course. What do you want to talk about?
Martha: I dunno, anything. What you had for breakfast, what you watched on telly last night, how much you're gonna kill Dad next time you see him. Anything.
(Riley and Martha are in the jettisoned escape pod)
Riley: The wonderful world of space travel. The prettier it looks, the more likely it is to kill you.
Martha: He'll come for us.
Riley: It's too late. Our heat shields'll pack in any minute and then we go into free-fall. We'll fall into the sun way before he has a chance to do anything.
Martha: You don't know the Doctor. I believe in him.
Riley: Then you're lucky. I've never found anyone worth believing in.
Martha: No girlfriend? Boyfriend?
Riley: The job doesn't lend itself to stable relationships.
Martha: Family then?
Riley: My dad's dead. I haven't seen my mum in six years. She didn't want me to sign up for cargo tours. Things were said and since then… all silent. She wanted to hold on to me, I know that. She's so stubborn.
Martha: Yeah, well, that's families.
Riley: What about you?
Martha: The works. Mum, dad, dad's girlfriend, brother, sister. No silence there. So much noise. (starts to tear up) God, they'll never know. I'll just have disappeared and they'll always be waiting.
(McDonnell comes face to face with the possessed Korwin)
McDonnell: Korwin? What are you? Why are you killing my crew? What did you do to him? What have you done to my husband? (Korwin stops) You recognise me? Korwin, you know me. It's Kath, your wife.
Korwin: My wife?
McDonnell: That's right. You're still in there. Your wife.
Korwin: It's your fault.
McDonnell: Is the infection permanent? Can you cure him?
The Doctor: (after a long pause) I don't know.
McDonnell: Don't lie to me, Doctor. Eleven years we've been married. We chose this ship together. It keeps me honest, so I don't want false hope.
The Doctor: The parasite's too aggressive; your husband's gone. There's no way back. I'm sorry.
McDonnell: Thank you.
The Doctor: Are you certain nothing happened to provoke this? Nobody's working on anything secret? 'Cause it's vital that you tell me...
McDonnell: I know every inch of this ship. I know every detail of my crew's lives. There is nothing.
The Doctor: Then why is this thing so interested in you?
McDonnell: I wish I knew.
Erina: (after Ashton gives her orders over the intercom) Whatever you say, 'boss'. Go there. Come back. Fetch this. Carry these. Make drinks. Sweep up. Please… kill me now.
(The possessed Korwin appears beside her)
Korwin: Burn with me...
(The Doctor, McDonnell and Scannell find the vapourised Abi Lerner in the medical centre)
The Doctor: Burn with me.
Scannell: That's what we heard Korwin say.
McDonnell: What? You think… No way! Scannell, tell him! Korwin is not a killer. He can't vapourise people. He's human!
The Doctor: (reading the test results) His bioscan results. Internal temperature, one hundred degrees. Body oxygen replaced by hydrogen. Your husband hasn't been infected; he's been overwhelmed!
McDonnell: The test results are wrong!
The Doctor: What is it, though? A parasite? A mutogenic virus? Something that needs a host body, but how did it get inside?
McDonnell: Stop talking like he's some kind of experiment!
The Doctor: Where has this ship been? Have you made planet floor recently? (McDonnell shakes her head) Docked with any other vessels? Any sort of external contact at all?
McDonnell: What is this, an interrogation?
The Doctor: We've got to stop him before he kills again.
McDonnell: We're just a cargo ship!
The Doctor: The power's still working, the generator's going, if we can harness that… ah!
McDonnell: Use the generator to jumpstart the ship.
The Doctor: Exactly! At the very least, it'll buy us some more time.
McDonnell: That is brilliant.
The Doctor: I know! (to Scannell) See, tiny glimmer of hope.
Scannell: If it works.
McDonnell: (to Scannell) Oh, believe me, you're gonna make it work.
The Doctor: (via intercom) Martha, be careful. There may be something else aboard the ship.
Martha: Anytime you want to unnerve me, feel free.
The Doctor: (via intercom) Will do, thanks.
Martha: What are you typing?
Riley: These doors' trip-codes the answer to a random question set by the crew. Nine tours back, we got drunk, thought them up. Reckoning was if we're hijacked, we're the only ones who know all the answers.
Martha: So you type in the right answer…
Riley: This sends an unlock pulse to the clamp, but we only get one chance per door. Get it wrong; the whole system freezes.
Martha: Better not get it wrong then.
Riley: The oldest and cheapest security system around, eh, Captain?
McDonnell: Reliable and simple. Just like you, eh, Riley?
Riley: Try and be helpful, get abuse. Nice.
McDonnell: The auxiliary controls are in the front of the ship
Scannell: There's twenty-nine password-sealed doors between us and them. We'd never get there in time.
Martha: Can't you override the doors?
Scannell: No. 'Sealed closure' means what it says. They're all deadlock sealed.
The Doctor: So a sonic screwdriver's no use.
Scannell: Nothing's any use. We've got no engines, no time and no chance.
The Doctor: Oh, listen to you! Defeatist before you even started! Where's your Dunkirk spirit?
The Doctor: Oh, we're in the Toraji system, lovely. You're a long way from home, Martha. Half a universe away.
Martha: Yeah, feels it
The Doctor: And you're still using energy scoops for fusion. Hasn't that been outlawed yet?
McDonnell: (off Riley's look) We're due to upgrade next docking.
The Doctor: Thank you.
Martha: Don't mention it.
The Doctor: (regarding the ship) Now that is hot!
Martha: It's like a sauna in here...