Also, the water would be pretty cold. Shivering!Doctor? I'm not sure why, but I really like that idea. Does that make me kind of a sadist? I hope not...

Yeah, I suppose anyone would seem more of a threat to security than Martha's Foolish Family. Plus he's been a Very Bad Man and the Master is displeased.

Empire is my favourite too, I have real trouble making it through RotJ without falling asleep!