The short version
The CCTV feed is the evidence layer that catches what the window hides. The community wiki's camera list covers black eyes, unnaturally bent bodies, patients staring into the camera, void-black bodies, twitching feeds, a Security Camera Mimic standing in the camera room, and mismatched ears or faces that belong to a different species than the patient you checked in person. Any one of these is a reject: close the shutters.