Right right, sometimes Lucie forgot how to actually talk to people. "Sorry mate, I was bein a bit rude, yeah? Right then, you're on board the TARDIS. It's a .. space ship. You'r gonna figure I'm a nutter, but you can have a look around. It's definitely a space ship. We're in space. In another universe."
Might as well say it all at once, like ripping off a bandaid.