Jack tells Lisa that "I'm sorry for what they did to you but this ends now, tonight." These are the exact same words used by the President of Great Britain (Don Warrington) when he spoke to the recently converted Cybermen in the 2006 Doctor Who episode "Rise of the Cybermen".

Toshiko: All I'm saying is, once in a while, I'd like to drive!
Owen: And all I'm saying is no!
Toshiko: Why not?!
Owen: Look, I've shared cars with women before. I know what'll happen. There'll be an emergency, we're all raring to go, I jump in, what do I find? Seat's in the wrong position, the rear view mirror's out of line and the steering wheel's in my crotch. Time it takes to sort it all out, aliens'll have taken Newport.

Jack: Ianto...come in, Ianto. I need to hear those beautiful Welsh vowels!

Jack: Execute her or I'll execute you both!
Ianto: You think you're some kind of hero, but you're the biggest monster of them all!

Gwen: You would never have shot him, not really.
Jack: Wouldn't I?
Gwen: Would you have shot me if I'd gone to stand by him?
Jack: But you didn't.
Gwen: If I had, though.
Jack: But you didn't.

Gwen: So have you ever loved anyone, that much?
(Jack doesn't answer)
Gwen: When she had hold of you, I thought just for a moment I thought that maybe you could die after all.
Jack: Wanna know a secret?
Gwen: Hmm.
Jack: So did I...and just for a second there, I felt so alive.