I think it's the cafeteria. But no worries you will know it because when you enter there will be scene where a girl hangs from the ceiling by a kinda of bug. At this place it is best to run to upstairs and past that place, AND, I repeat AND don't stand there like Rambo and start blasting eveything.
The monsters won't stop coming. Go find fuse and fix the lights. The fuse will be at the end upstairs guarded by a big leg thing. The fuse box will be at where you came up from.Just quickly fix the thing and get the lights back on.Then you have done it. Go search the whole cafe to find ammos and stuuf then when you are done go to the nurse lady.