A/N: This one amuses me :) Enjoy! :D
"Doctor?" John knocked on the TARDIS doors. When there was no response, John gently pushed them open. He figured that if the Doctor really didn't want anyone to get inside he would have locked up.
"GAH!" the Doctor shouted. He was naked. Completely nude. Holding up a pair of plain blue swimming trunks which he had obviously just taken off. There was a purple towel on the counsel with what looked like dolphins printed on it and a pile of what was presumably the Doctor's clothes on the chair.
"Sorry! Sorry!" John exclaimed, clapping both hands over his eyes while the Doctor hastened to drop the trunks to waist level.
"Probably should have expected that, seeing as how I left the doors unlocked," the Doctor said apologetically.
"Sherlock said you were in the library!" John yelled, using one hand to grope for the door and slam it shut.
"Yeah, well, fancied a bit of a swim instead of books. Anyways, I was in the library." The Doctor dropped the trunks and wrapped the towel around his waist.
"You just said you'd fancied a swim instead!" John peeked out to check if it was safe to look, then tentatively lowered his hands.
"Well, yes. The pool is in the library."
"Sherlock says…" John rubbed a hand over his face, "Sherlock says that there are cameras in the flat, at least two. Put there by the person who sent the phone and note."
The Doctor, who was struggling into his shirt, looked up. "What?"
"Yeah. At least one that can see into the kitchen, and one into the living room."
"Well, we have to be careful about what we do, then."
"Yep. I'm-I'm going to go now," John said, seeing that the Doctor was about to drop the towel to put on a pair of underpants.