[voice]
[There's plenty of things that can go through someone's mind when they don't remember how they got to where they are now, even if that's the safety of their own bed.
For Reid, his imagination got a few different things to draw inspiration from aside from the traditional "very wet night", and as soon as he wakes up said imagination flares to life. A near decade of crime scene photos tucked away coupled with an overhanging threat of mental illness and a constant fear of the dark does not for a calm Doctor make, and in the short moment it takes him to get up on his feet with a wince (Bruise from a baton. This is happening) his breath is already edging towards the shallow and rapid.
Something is very wrong, and so he reaches for the communicator, doing the first thing that comes to mind after strapping the holster back on and checking his gun for ammunition.]