There is a safer way to do it without risking crashing your chopper (and you can do that one with both choppers).
Drive straight into the 2nd "column" (the brown things above the black lamps) starting from the flag position.
Dive until your chopper starts to point downwards due to the stairs behind you.
Switch to gunner seat. The chopper will fall straight thru the wall and you just have to exit it, without risking it crashing on you.
I'll make a video.
http://www.youtube.com/watch?v=AAjrFsSVhLA
Note that it's MUCH MUCH harder with the MEC chopper, but it can be done.