And here it is. I may add rails to most of the new catwalk as it just looks odd being completely unguarded, maybe some props too.
And here's the external balconies for the ladders, which are barely big enough to accommodate the door, ladder and player. These things already jut out quite a bit, and a fire escape would have to be twice as big at a minimum, and even bigger if it were to be lag-friendly!
Since this is using the same door zone as the Airfield roof, you can actually stand pretty close to the door and not trigger it.
I may reduce the possibility of accidental triggering even further though by moving the upper floor PCTs/spawn points one metre closer to the MCT.