Other mistake: Before the security guard is killed, he turns around and faces the direction of the camera. He is killed, and the camera backs up to reveal 6 men standing there. The security guard would have seen the men and he had time to react to them, but did nothing. (00:32:50)
Other mistake: When everyone is mounting Lefty after escaping the temple, part of the lava flow directly on the right of the opening goes nowhere and just ends halfway down the screen.
Other mistake: The first victim of the mask in the series falls back against crates that must be made of dry leaves, since all it takes is for the body to lean against them to utterly shatter them. (00:18:55)