Or you can just f8 into the building because you're an admin.
Go to event menu. Change the top event from Unrestricted to Admin, and on the event with a 3000 next to it change it to 50.
Why change it to 50? Besides, if he's desperate to keep people out (even while he's entering the building which he'll be in the way for) he can use setplayertransform events.
Other than making little games where someone has to control something to make the game work, I never seen any good purpose for an admin room.