Well, it's obviously Sherlock and not Tony, even Cal can tell that much. (Of course, it could always be another double, this is Milliways, but that's too many options for Cal to deal with right now. Besides - it's obviously Sherlock, being even more . . . Sherlock-y than the one back in his room.)

A timeline thing? He's heard those happen here. Okay. He can work with that.

"Hi," he says, glancing back at his door.