yer so in tops casino in bennys hidden room there is a pass way that leeds to a door on the map it says vault 21 but the door its self says sub basemant. anyone know whats up with this or even better where the key is ?

I would also love to know where the key is for the sub-basemant, im itching to explore it

I and a couple other people investigated this. There is no key to the basemant elevator. It's apparently an unfinished area that was cut from the game at some point.

It's nothing you can explore, it's just Benny's escape route.