The TARDIS? Oh, aye, that's right. I'd not remembered when I saw it. Look, do ye remember when I found that funny looking console in the park? The one ye wanted to press all the buttons on?

And aye, I am, but we're in a cave. It's not very exciting. [He turns the CAT, though, so the lad can see the cave wall. Which looks mostly like rock, with maybe a little crystal worked into it.]