Okay, I LOVE the idea of timers on a game like this. It really creates the sense of urgency and frantic energy that I think someone would have in a "final girl" sort of scenario!
I think the idea of using something a can of sparkly water (or beverage of choice, maybe you want something stronger after finishing a harrowing game!) would be a really interesting mechanic for a timer. lol Could even go so far as to specify the Liquid Death canned water brand, just to be real on the nose.