That's interesting. Why would they do that? I mean if somebody is willing to break through a balcony, traversing between floors shouldn't be a big problem. And the second balcony is quite far away, there could be the same secure entrance between it and the room, as the floor entrance (If you can't just get there through the elevator). Maybe it's more about being able to see people who work there?
That could be, although in the time I've been here I've seen people out on those balconies maybe twice, and one of those was when they were installing a microwave antenna. I get the impression they are there mostly as a place to shelter in an emergency.
Edit: Typically the stairs and elevators in buildings like that are pretty well locked down to prevent unauthorized access from inside. The elevator probably opens into a small lobby with heavy locked doors blocking access to the rest of the floor. The balcony doors may not have been so well secured.
