When Murphy is sitting in her chair upstairs against the door, the door handle is on the right, above her left shoulder. As Garnett is pushing on the same door from the other side, the handle is also on the right where it should be on the left.
Early in the episode, several zombies are seen coming down a hill away from the incoming tornado. A few of these zombies appear at least twice in shot, showing they have been superimposed on the scene multiple times.