In the scene where Mary Beth opens the hatch in the submersible while she is stuck, the shots from inside the submersible show her hair wet and flat against her head, while the shots from outside the submersible show her hair still curly and dry.
Almost at the end of the movie when Terry and Mary Beth are talking on the phone, the ceiling fan is visible and is on. It's on for four scenes, off for two and then goes on again.