There's another group near the start. Blow up the explosive can on your side so that they can't blow it up and then take cover by the wall and start fighting. There are a few elites and a few engineers. Just keep firing. Stay down and take them all out. There's plenty of cover and there are several explosive barrels to shoot on the other side.

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Advance and hit the mechs ahead. You should be able to punch right through. Look around for a submachine gun upgrade and loot the locker. There's another big occupied area ahead. Take cover and start shooting again. There are a ton of mercenaries around and a few waves should come up through the crates. You should have a fine killing zone to just take your time and wear them all down.
Go to the other side and scan a mercenary to get a boost to your medi-gel upgrade. Go into the shack and hack the terminal for some more money, then advance through the crates. There should be a few mercenaries left to kill. Just cut right through them and keep going. You shouldn't have any trouble.
The next batch is just beyond another conveyor line. Don't go down into the trench just yet. Take cover on the wall and start shooting. They should come in waves with a lot of heavies and engineers, but it should just be another killing shield.
Go down into the trench and cut over to the elevator. A few more mercenaries will come out of the elevator, but they really love to hide behind explosive stuff, so just start some fires and take them down. Jump into the elevator and ride it up to Niket, Oriana, and Enyala.