Plot hole: Jim taking over Sam's body just doesn't make any sense. It's plausible for a spirit to temporarily take over a living body, but a dead body is dead for a reason. It can't sustain life anymore. Death isn't a temporary ailment. It's permanent. What should have happened was the same thing that happened when another ghost took over a recently deceased person, which happened in a previous episode. The dead body would decay and start to lose function. Sam's body suddenly gaining back the properties of life is completely inconsistent with what we're led to believe in the setting of the show.