This level, for me at least, contains the hardest and most frustrating part of the game, especially on Hard. Near the end of the level you will face 6 "Fat Boys" aka the big rocket Trigens and 4 Locust who jump around. However there is a great trick to make things much easier if you are struggling in this section.
Right before this area, and after taking the elevator up, you will see a huge amount of ammo, guns, health ect. behind a gate. Load up (rocket launcher, sniper, LMG, AG36 AR preferably) then push one of the desk chairs in this room down the hall to the two big doors that you need to open. Open the first door but DO NOT open the second door. Instead put the chair in the first door way so that it 'glitches' and makes the door keep opening and closing. Once the first door is glitching, open the second door and run back to to to entrance of this room.
Now, 4 Fat Boys should come to the door and get stuck making them easy targets for you to kill. The rocket launcher kills them quickly, also if they fire rockets just run back in to hallway. Once they are dead, use Cry-Vision to find and snipe the Locust. Get more ammo from the armory if needed then head back and run down the left side of the big open area. Once you get close to the big door in the back, 2 more Fat Boys will come out. Deal with them (run back up if you need, they should follow you) then activate the elevator.
I hope this enough detail, if not please refer to the video below. I take NO credit for this trick, just wanted to share it with anyone who plays this game.
All credit to YT: MoldyJacket