[Anonymouse]

Yes, Lady Christina was definitely from the Tomb Raider stable. But with that figure, and those beautiful blue (blue-grey?) eyes, who cares?

Actually, yeah, we do, okay; character more important than looks, of course. But she was, again, the sort of companion the Doctor needs, viz. someone who isn't overawed by him, who isn't in the least afraid to talk back to him, but who nonetheless respects him. Once again, though, he loses out, undeservedly. Dramatically necessary as it might have been, I still find it hard to forgive Astrid's...death? Ascendence? - being written out, anyway; she'd have had a lot of fun with the Doctor and so, I imagine, would he.

Michelle Ryan was, like Billie Piper and Catherine Tate before her, a pleasant surprise; she carried herself very well. Lovable rogues we've seen aplenty, but a female one is a nice change. Unfortunately, thanks to her the Doctor is now effectively a wanted criminal (though his affiliation with UNIT might get him off the hook there)!

And hands up anyone who hasn't figured out what "he will knock four times" means...oh, yes, now there's something to look forward to...!