I just had a passing thought. What do you think about making it semi free roam? Like occasionally, maybe once or twice per night depending on what night it actually is, you would have to leave the office to go clean something up or go repair a generator or restock supplies somewhere etc? I feel like throwing that in with the doors and lights formula we've all come to know and love would make for a more tense and original experience. Not trying to force this or scream at you to add it or anything I know how much of a pain in the ass it would be to even start to think about how to implement something like that but it was just a suggestion I wanted to type out to give you some more creative fuel.

(Thanks for your time)