DUNBAR: Since you seem to have it all sewn up, Doctor, perhaps you can tell us where the pod is now?

DOCTOR: I'll make a guess. Right here, in this country. Action! Action, that's what we need. If we don't find that pod before it germinates, it'll be the end of everything. Everything, you understand? Even your pension!

SARAH: Ah, this isn't Cassiopeia.

DOCTOR: It's Antarctica.

SARAH: We're back where we started!

DOCTOR: Yes.

SARAH: We won't get a suntan here.

DOCTOR: No.

SARAH: You forgot to cancel the coordinate programme, didn't you.

DOCTOR: Yes.

SARAH: Shall we try again?

DOCTOR: Yes. Just a minute.

SARAH: What?

DOCTOR: Have we been here before, or

BOTH: Are we yet to come?