[Sherlock snorts when Joan asks about the cameras.]

We've been caught on the security cameras since we got here. If they haven't noticed us yet, it's doubtful that will change.

[The plan isn't exactly full-proof, but with stationary cameras it's incredibly difficult to get through the entire path without showing up in the footage without implementing their own looped clip. Unfortunately they hadn't had time to stop by the video room and it would be too dangerous to go back now.]