Dr. Whitley refers to the knife he bought his son Martin as a switchblade, but the knife Martin found and shows him in a picture is a standard folding knife.
Every time the red (outer) door is open or visible, it's apparent that it faces another door across the hall just a few feet away. But when the cameraman shoots straight through the red door's window, his camera shows a long hallway with T junction where a hospital worker has been dragged, leaving streaks of blood on the floor. When Malcolm carries the camera through the same door, he is in the original hall, with the closed door on the opposite side again.
When Malcolm holds up a photo of a lock-blade hunting knife, Martin refers to it as a switchblade.