How about the constant quiet stare at the killer and then doing something?
Not immediately calling the police
The police somehow failing at/not doing their job, killed easily, and/or fits in the "Doubter" archtype
Phones either not working or conveniently at low power to die at just the right time when their needed (especially if they have not been used for nearly the whole movie)
The protags getting a weapon to defend themselves, then not use it at all or just drop it after one use
If the protags are or one of them is athletic, but not really showing/pulling the hussle.