Air Boat Area: After getting gun

[Staino]

I made it through after getting the gun mounted to the airboat, shot up the chopper went through a tunnel killed more dudes. I came to this section where I got ambushed by these two gates coming down. They are closed and I cant seem to find a way to open them. There is a storage room with four shelves that you can knock over and a bench.

 

[tommycat]

You can airboat up the fence fragment onto the walkway to your right(as you entered), and just jump from there.

 

[Sulkdodds]

I'm not quite sure where you are...do a load of Combine run out behind you and shoot at you from the walls? Is there a row of pillars to your right when you come in? If so then there should be a metal grating ramp just on your right as you enter the area. Drive up it, along between the pillars and the wall, out between some wire mesh fences and speed away to freedom.

If not, then I have no idea where you are. :|

EDIT: Oh, the other guy said. Yeah, drive up the ramp.