Salana says that drinking is not allowed on the site, however later on in the episode a drunken visitor tells Salana that it is an open bar.
Donna's comparison of the TARDIS to Halpen's rocket- 'You've got a box; he's got a Ferrari'- is similar to the Doctor's comparison between the TARDIS and Captain Jack's Vortex Manipulator in Utopia (in which he says 'I've got a sports car, you've got a space hopper'.)
Several references are made to The Impossible Planet and The Satan Pit (the previous episodes to feature the Ood), such as the Doctor referring to the stronger power overtaking the Ood as 'The Devil' and him mentioning that he had to let the Ood die.
Donna mentions the bees disappearing in modern day Earth for the second time, the first being in Partners in Crime.
It is never actually explained how the Ood were able to use the translator as a weapon.
Ood Sigma: Take this song with you.
Donna: We will.
The Doctor: Always.
Ood Sigma: And know this, Doctor-Donna, you will never be forgotten. Our children will sing of the Doctor-Donna, and our children's children, and the wind and the ice and the snow will carry your names forever.
The Doctor: Funny thing, the subconscious. It takes all sorts of shapes. It came out in the red-eye as revenge. Came out in the rabid Ood as anger. And then there was patience. All that intelligence and mercy focused on Ood Sigma. How's that hair loss, Mr Halpen?
(Halpen reaches to his head and pulls a clump of hair out)
Halpen: (speaking to Ood Sigma) What have you done?
The Doctor: Oh, they've been preparing you for a very long time.
(In Warehouse 15, the Doctor and Donna find a massive brain)
The Doctor: The Ood Brain. Now it all makes sense. The missing link. The third element, binding them together. Fore-brain, hind-brain and this. The telepathic centre. It's a shared mind, connecting all the Ood in song.
(Halpen advances on them, holding a gun)
Halpen: Cargo. I can always go into cargo. I've got the rockets; I've got the sheds. Smaller business, much more manageable. Without livestock.
Dr Ryder: He's mined the area.
Donna: You're going to kill it?
Halpen: They found that… thing centuries ago beneath the northern glacier.
The Doctor: Those pylons…
Donna: In a circle. The circle must be broken.
The Doctor: Dampening the telepathic field. Stopping the Ood from connecting for two hundred years.
Halpen: And you, Ood Sigma, brought them here. I expected better.
Ood Sigma: My place is at your side, sir.
Halpen: Still subservient. Good Oo…
Donna: If that barrier thing is in place, how come the Ood started breaking out?
The Doctor: Maybe it's taken centuries to adapt? The subconscious reaching out?
Dr Ryder: But the process was too slow. Had to be accelerated. You should never have given me access to the controls, Mr Halpen. I lowered the barrier to its minimum. Friends of the Ood, sir. It's taken me ten years to infiltrate the company and I succeeded.
Halpen: Yes. Yes, you did.
(Halpen throws Ryder over the side and onto the Ood Brain, which absorbs him)
Halpen: Change of plan.
Dr Ryder: There's no reports of trouble off-world, sir. It's still contained to the Ood-Sphere.
Halpen: Then we have a public duty to stop it before it spreads.
The Doctor: What's happening?
Halpen: Everything you wanted, Doctor. No doubt there'll be a full police investigation once this place has been sterilized so I can't risk a bullet to the head. I'll leave you to the mercies of the Ood.
The Doctor: But, Mr Halpen, there's something else, isn't there? Something we haven't seen.
Donna: What do you mean?
The Doctor: A creature couldn't survive with a separate fore-brain and a hind-brain. They'd be at war with themselves. There's got to be something else. A third element. Am I right?
Halpen: And again, so clever.
The Doctor: But it's got to be connected to the red-eye. What is it?
Halpen: It won't exist for very much longer. Enjoy your Ood.
Halpen: The Ood were nothing without us, just animals roaming around on the ice.
The Doctor: That's because you can't hear them.
Halpen: They welcomed it. It's not as if they put up a fight.
Donna: You idiot. They're born with their brains in their hands. Don't you see? That makes them peaceful! They've got to be, 'cos a creature like that would have to trust anyone it meets!
The Doctor: Oh, nice one.
Donna: Thank you.
Halpen: The system's worked for two hundred years. All we've just got a rogue batch, but the infection is about to be sterilized.
Halpen: Mr Kess. What's the situation?
Kess: We've contained it, sir. Fenced them in. But the red-eye seems to be permanent this time, its not fading. Worse than that, sir, there's more of them turning rabid. In my opinion, sir, I think we've lost them. The entire batch contaminated.
Halpen: What's causing it? Why now? What's changed? (He looks in the mirror and pulls a clump of hair out) How many Ood in total?
Kess: I'd say about two thousand, sir.
Halpen: Well, we can write them off. That's what insurance is for. (to Ood Sigma) Drink. (to Kess) There's plenty more on the breeding farms. Let's start again. (downs the drink given to him) Fetch the canisters. No survivors.
Donna: If people back on Earth knew what was going on here…
Solana: Don't be so stupid. Of course they know.
Donna: They know how you treat the Ood?
Solana: They don't ask. Same thing.
The Doctor: Solana, the Ood aren't born like this. They can't be. A species born to serve could never evolve in the first place. What does the company do to make them obey?
Solana: That's nothing to do with me.
The Doctor: Oh, what? 'Cause you don't ask?
Solana: That's Dr Ryder's territory.
The Doctor: Where's he? What part of the complex? I could help with the red-eye. Now show me.
Solana: There. Beyond the red section.
The Doctor: Come with me. You've seen the warehouse, you can't agree with all this. You know this place better than me. You could help.
(Solana looks at the Doctor and Donna)
Solana: They're over here! Guards! They're over here!
(The Doctor and Donna find a large contained filled with Ood ready to be shipped)
Donna: A great big empire built on slavery.
The Doctor: It's not so different from your time.
Donna: Oi, I haven't got slaves!
The Doctor: Who do you think made your clothes?
Donna: Is that why you travel round with a human at your side? It's not so you can show them the wonders of the universe, it's so you can take cheap shots!
The Doctor: Sorry.
Donna: Well, don't. Spaceman. (to an Ood) I don't understand. The door's open. Why don't you just run away?
Ood: For what reason?
Donna: You could be free.
Ood: I do not understand the concept.
Donna: What is it with that Persil ball? I mean, they're not born with it, are they? Why do they have to be all plugged in?
The Doctor: Ood, tell me. Does the circle mean anything to you?
All Ood: The circle must be broken.
Donna: Oh, that is creepy.
The Doctor: What is it? What is the circle?
All Ood: The circle must be broken.
The Doctor: Why?
All Ood: So that we can sing.
(The Doctor and Donna see Kess mistreating some of the Ood)
Donna: Servants? They're slaves!
The Doctor: Last time I met the Ood, I never thought. Never asked.
Donna: That's not like you.
The Doctor: I was busy. So busy I couldn't save them. I had to let the Ood die. I reckon I owe them one.
(Dr Ryder, Ood Sigma and Mr Halpen inspect the rabid Ood)
Halpen: What the hell is wrong with it?
Dr Ryder: It's obviously Stage Two of red-eye. Whatever that means.
Halpen: Ood Sigma, have you seen this before?
Ood Sigma: Humanity defines us, sir. We look to you for answers.
Halpen: Ah, fat lot of good, all of you. We're exporting hundreds of thousands of Ood to all the civilized planets. If they turn rabid, you know what it'll mean.
Dr Ryder: Well, there's only one thing I haven't checked, sir. Warehouse 15.
Halpen: (sounding nervous) Why should that cause trouble? It's been two centuries now, no change. Not ever.
Donna: Are there any free Ood? Are there Ood running wild somewhere, like wildebeest?
Ood: All Ood are born to serve. Otherwise we would die.
Donna: You can't have started like that. Before the humans, what were you like?
The Doctor: The year 4126. That is the Second Great and Bountiful Human Empire.
Donna: 4126? It's 4126. I'm in 4126!
The Doctor: It's good, isn't it?
Donna: What's the Earth like now?
The Doctor: Bit full, but you see the Empire stretches out across three galaxies.
Donna: It's weird. I mean, it's brilliant, but back home, the papers and the telly, they keep saying we haven't got long to live. Global warming, flooding, all the bees disappearing…
The Doctor: Yeah, that thing about the bees is odd.
Donna: But look at us. We're everywhere. Is that good or bad, though? I mean, are we explorers or more like a virus?
The Doctor: Sometimes I wonder.
Solana: At heart, what is an Ood, but a reflection of us? If your Ood is happy, then you'll be happy too.
The Doctor: The Ood are harmless, they're completely benign, except… the last time I met them, there was this force- like a stronger mind- powerful enough to take them over.
Donna: What sort of force?
The Doctor: Ah. Long story.
Donna: Long walk.
The Doctor: It was the Devil.
Donna: If you're going to take the mickey, I'll just put my hood back up.
Donna: What's an Ood?
The Doctor: They're servants of humans in the forty-second century. Mildly telepathic, that was the song, it was his mind calling out.
Donna: I couldn't hear anything. He sang as he was dying.
The Doctor: His eyes turned red.
Donna: What does that mean?
The Doctor: Trouble.
Donna: (as Halpen's ship flies overhead) Blimey, a real proper rocket! Now that's what I call a spaceship! You've got a box; he's got a Ferrari!
The Doctor: Millions of planets, millions of galaxies and we're on this one. Molto bene. Bellissimo. You said it, Donna. Born in Chiswick, a life of work and sleep and telly and rent and tax and takeaway dinners, all birthdays and Christmases and two weeks' holiday a year and then you end up here. Donna Noble, citizen of the Earth, standing on a different planet.
(After a very bumpy ride, the TARDIS lands)
The Doctor: Set the controls to random. Mystery tour. Outside that door could be any planet, anywhere, any when in the whole wide… are you alright?
Donna: Terrified. I mean, history's one thing but an alien planet…
The Doctor: I could always take you home.
Donna: Yeah, don't laugh at me.
The Doctor: I know what it's like. Everything you're feeling right now, the fear, the joy, the wonder, I get that.
Donna: Seriously? After all this time?
The Doctor: Yeah! Why do you think I keep going?
(An Ood hands Mr. Bartle a file)
Mr. Bartle: I said military figures. That's the domestic file. Get me the military.
(The Ood slams the file on the desk. We see it's eyes have gone red)
Ood: The file is irrelevant, sir.
Mr. Bartle: Oh, and why's that?
(The Ood pushes the translator ball onto Bartle's head, electrocuting him)
Ood: Have a nice day.
Advert Announcer: The Ood. They came from a distant world. They voyaged across the stars. All with one purpose…
(cut to an Ood, holding out a cup of tea)
Ood: Do you take milk and sugar?
Solana: Now then, Dr Noble, Mrs Noble, if you'd like to follow me.
The Doctor: Oh no, we're not married.
Donna: We are so not married.
The Doctor: Never.
Donna: Never ever.
Donna: It's weird, but being with you, I can't tell what's right and what's wrong anymore.
The Doctor: It's better that way. People who know for certain tend to be like Mr. Halpen.
The Doctor: What is that stuff?
Ood Sigma: Ood graft suspended in a biological compound, sir.
Mr. Halpen: What the hell does that mean?
The Doctor: (very slowly, as he begins to understand) Oh dear.
The Doctor: Oh, I've sort of got a song of my own, thanks.
Ood Sigma: I think your song must end soon.
The Doctor: Meaning?
Ood Sigma: Every song must end.
The Doctor: ...yeah.
(The Doctor and Donna are tied up and left by Halpin. The Doctor struggles with his restraints as Donna grows impatient)
Donna: Well do something. You're the one with all the tricks. You must have met Houdini.
The Doctor: These are really good handcuffs.
Donna: Well I'm glad of that. I mean, at least we've got quality!
Donna: (to The Doctor) I spent all that time looking for you, Doctor, because I thought it was so wonderful out there. I wanna go home.
Donna: They...they turned him into an Ood!
The Doctor: Yep.
Donna: He's an Ood!
The Doctor: I noticed...
The Doctor: Where'd you learn to whistle?
Donna: West Ham, every Saturday.
Donna: Are you all the same?
Ood: I don't know what you mean, Miss.
Donna: Why are you calling me "miss"? Do I look single to you?!
Overnight UK viewing figures for this episode were 6.9 million, with the final viewing figure at 7.50 million.
United States: 9 May 2008
Australia: 20 July 2008
New Zealand: 27 July 2008
Turkey: 20 February 2011
Some of the marketing graphics used by the company have a strong stylistic resemblance to work by Andy Warhol. For example the artwork behind the PR woman, Solana, as she stands on the pedestal giving her presentation to the buyers.
Donna: What is it with that Persil ball?
Persil is a brand of clothes washing powders and liquids that are designed to be delivered to the wash via a palm-sized dosing ball.
Donna: Rough Guide to the Ood-Sphere? Works for me.
The Rough Guide series of travel books cover more than 200 destinations. The series began with the 1982 Rough Guide to Greece, a book conceived by Mark Ellingham, who was dissatisfied with the polarisation of existing guidebooks between cost-obsessed student guides and "heavyweight cultural tomes". Initially, the series was aimed at low-budget backpackers but are now marketed to travellers on all budgets. The initial focus on travel has broadened to a coverage of reference subjects, including film, literature, popular science, ethical living and Shakespeare amongst others.
Solana: Ood, you dropped something.
The Ood's "comedic speech" option references the catchphrase of Homer from The Simpsons.