Character mistake: Just after the shootout between the robbers and the armored truck drivers at the dip in the road, the teacher that is with the robbers pumps the shotgun about 3 times, without firing a shot after they crossed the water. This would just waste a perfectly good cartridge, since they hadn't been shot yet.
Hard Rain (1998)
1 character mistake - chronological order
Directed by: Mikael Salomon
Starring: Morgan Freeman, Christian Slater, Randy Quaid, Minnie Driver
Continuity mistake: Near the end when Karen is handcuffed to the banister, in one shot her hands are handcuffed but not to the banister. This is before Tom shoots the handcuffs to free Karen.
Answer: Because the Sheriff wanted to kill everyone, leaving no witness. Remember the old saying, "The Enemy of my Enemy is my Friend."