There’s a so-called “Haunted House Problem” that plagues many horror movies. When it’s clear something is awry, why don’t the inhabitants of the spirit-riddled dwelling just leave? Why won’t they take heed of all the signs we see and are screaming at the screen to them about? Why are they blithely preparing pot roast? The films that work best are the ones where they know but can’t escape, because they’re in the wilderness, night has fallen, and the car won’t start, or they’re trapped on a spaceship with a captive alien with acid for blood that manages to get loose.