(at around 1h 9 mins) When Jack and Quentin are holding pistols at each other crossed at their wrists, Quentin's pistol repeatedly switches from his right to his left hand throughout the scene as they argue verbally.
(at around 35 mins) The green hospital door is not locked, otherwise the handle wouldn't move; it actually opens.
Although they are supposed to be trapped on the 3rd floor of the hospital, the directional signs in the hallway indicate they are on the 2nd floor.
(at around 1h 16 mins) In the final scene, Candace drives while Jack is in the back seat of the car. They discuss that "maybe there are some leap year babies in the next town over" yet there are multiple vehicles passing their vehicle on the road, and much traffic seen in the background. For a town that is not supposed to have any rational people, they have too many background cars following traffic laws for the plot to stick in this scene.