In Benny's Suite, at The Tops, if you go in the room where you first find Yes Man, there's a door. Through that door is 2 other doors that cannot be opened (Aren't even real) and an elevator. To go through the elevator you need a key... Does anyone know what this is and where the key is perhaps?

I was just wandering that too. Couldn't find any info. The key was not on Benny when I found him in the Fort.

It leads to the sealed off section of Vault 21.

http://fallout.wikia.com/wiki/The_Tops