***SPOILERS***
I'm on a mission to disable the big gun right now. Blew the hangars already, and found the boss. I had to jump up above the trenches and drop in a hole to open the door so we could go through.
The door's open, we go right on the other side of it, and are in a small room with two other doors, which won't open for me. The boss is saying I have to find a way to open the door, which I assume means the next door, which he is looking at.
I've run around topside, tried nades, everything I can think of, and can't get any further. Anybody been past this yet?