Revealing mistake: When the cops watch the guy in the Santa costume being attacked their brakes are cut under the car but a few moments later when they drive off down the street they do apply the brakes to stop from the lights exploding above and the brakes do work.
Suggested correction: A cut brake line would not stop the brakes from working instantly. It would take a few pumps of the brakes for fluid to expel. So the brakes would work for a little while.