Right, so, I was stuck on this for about 3-4 days. Truly one of the hardest checkpoints I've ever seen. My situation was that I destroyed every single generator, and zero blisters, because I was dumb. Maybe you're in a similar situation?

Anyway, here was my strategy. It might not be too great, since I died probably 200-300 times, but I did eventually beat it.

The biggest problem is lack of ammo. To destroy all 8 or whatever blisters, you need a lot of firepower, and you can only carry enough boomshot or whatever on your person for like 2-3. The torque bow I finally realized gets you killed too much. I noticed that when you're hiding from the boss, the more often he catches you looking out of cover, or even blind firing, the more his machine gun hits you, and the far more likely his rockets are to roflstomp instagib you. He seems to target them higher if he sees you standing up, and once that happens, you're fucked.

So what did I do? Horde as much boomshot as I could.

You're gonne need: boomshot falling from sky, boomshot in back right corner, boomshot on right table, grenades on front right corner, grenades in front middle, boomshot by left stairs, and boomshot on left high corner. I'll explain.

When you spawn, there's a boomshot falling from the sky on the right towards the center of the room. Run to it, it has 2-4 shots randomly. Shoot the right leg twice to pop, this will be one of the harder shots to get later on, so get it off now. You will have time. Next, depending on how cheeky you feel, run to the boomshot in the backright corner room, or skip and just grab the one on the table. Or both. Try and squeeze in 2-4 more shots from this side of the room on the boss to take down more hard to get blisters. Here, it's a fight against the juvies rushing you to quickly get the ammo, make the shots, kill or run from them, and get out of there. I only had about a 25% successrate for this part, because you want to make it easier on yourself later by getting as much boomshot ammo and blisters killed early on. Once the drones advance, you need to be gone or you're dead.

Next, hug the outer parameter and snag the ammo box in the close right corner (from the starting position) if you need it, and the grenades on the cover nearby. Carefully run along the cover and move to the left side of the room, snagging the grenades near your spawn on the second major cover. If you spend even a moment longer out of cover due to not rolling, you'll probably die.

Haul ass up the stairs to the far left corner, and keep in mind you should have full boomshot, so don't pick up the boomshot here until you're down to 2 rounds. Watch your back for juvies and keep your lancer out most of the time. If a drone comes, you're likely fucked, but blindfire him to make him run away, and last ditch, roll or change cover and spray and pray. Be especially careful if marcus is off fucking around somewhere and not right by you.

Anyway, from here it's an endurance test. Try and pop a blister with every 2 shots, and limit your standing time as much as possible. Your last true test is to check that the coast is clear and run downstairs when you're boomshot is down to 2, snag the extra boomshot by the right of the foot of the stairs, and get back on up there. Blind toss frags when he gets close, and you might get a lucky hit.

But yeah, this fight was stupid. Literally a single mistake, a single instance of bad luck, and you're done. I nearly gave up, but once you do it it feels simple. It's all about ammo hording and preparation for a long and careful holdout. You don't wanna be in cover but with no ammo and the asshole has a blister on his back you can't see. I've been there too many times.