[Scrapyard planet]

(The travellers are using metal detectors.)

RYAN: We're never going to find one!
DOCTOR: Course we are. I've programmed the detectors specifically. I found seven last time I was here.
GRAHAM: And how long did that take you?
DOCTOR: It couldn't have been more than a month. Unless that was Seffilun 59.
YASMIN: Which one's this?
DOCTOR: Seffilun 27. Maybe 59's the one with a big pile of these. That's the problem with junk galaxies, all the planets look the same. It's hard to keep track.
GRAHAM: If we've wasted the last four hours on the wrong planet...
DOCTOR: Oi! Who took you rainbathing in the upward tropics of Kinstarno?
GRAHAM: Oh, no, no. Listen, that's amazing. I was just saying, like, needle... haystack.
DOCTOR: Yeah, you might be right.
GRAHAM: No, hold on. I've found something!

(The Doctor uncovers it, to reveal red flashing lights on what looks like a land mine.)

DOCTOR: I'm sorry.
YASMIN: What's he found?
DOCTOR: Nobody move. (scans it) If I can keep it in temporal lock... No, it's got too many sensors, it won't work. It was camouflaged! This is someone's idea of a nasty joke.
YASMIN: What is it?
DOCTOR: Sonic mine. It's counting down.
GRAHAM: How long we got?
DOCTOR: Three, two...