Revealing: After Dr. Lawrence cuts off his leg and is crawling towards the gun, if you look at his dismembered leg, you can make out the shape of his foot hidden beneath his ripped up slacks.

Continuity: When Adam pounds on Zep with the toilet seat, he grabs his shoulder in pain. In the first shot of him holding his shoulder, his hand is soaked in blood. In the second shot, however, his hand is much cleaner.

Continuity: When Alison gets the gun from Zep and aims it at him, the gun is in her left hand. In the next shot it's in her right hand, and then it moves back to her left hand again. This is not an artifact of changing camera angles, you can clearly see the different hands holding the gun.

Factual error: Dr. Gordon is seen in a close-up to be sawing through his leg, some inches above the ankle joint and the shackle around it. Considering the long bones of the leg (fibula and tibia) are very tough in a young man, it would take a long time to saw through by hand, during which Dr Gordon should have passed out from pain-induced hyperventilation then died from shock.