Factual error: When J.D. gets killed, Vince's leg shakes. Vince is suppose to be paralyzed. Even if he was extremely scared, his leg shouldn't have been able to move no matter how much he tried. It happens again later in the movie. (00:30:55)
Factual error: At the end when the two people are shooting at each other underwater, they both fire about four shots at each other. This isn't possible because a gun needs pressure to reload, or else it would jam after one or two shots. An episode of Mythbusters confirms this.