Other mistake: In the beginning the "host" tells the guests that if they don't survive the $10,000 due them for staying the night will be paid to their heirs. A short time later he says that the entire $50,000 pot will be split among the guests who are still alive at the end of the night.
Other mistake: When Lance leaves Nora to go have a meeting with the remaining people in the house and they accuse Loren of murder, his room is locked from the inside but when he returns he opens the door without any trouble.
Other mistake: Once Dr. Trent enters the bedroom where Mrs. Loren is lying down "dead", they begin talking. Trent says "At first I couldn't get Nora to protect herself with a gun." There is no scene in the movie where he tries to convince her to use the gun, Lance is responsible for that. (01:02:25)