If it is the hallway with the carrier forms, they are infinitely spawning unless you push forward. I just threw a grenade down the hall to blow them up and sprinted through avoiding enemies. If you keep going straight through the next door, there is an overshield you can pick up to help clear the hall for your partner.
We didn't use any sort of glitches, despawns, etc. I think we just got lucky with enemies, grenade and ammo drops, etc. We got REALLY lucky in the room where you have to destroy the four vents. Made it through there in something like 3 attempts.
Ugh, yes, I have it on the One, but I don't have the ability to get on tonight, sorry man. Putting the daughter down to sleep in a few mins and then some guys are over for the hockey game right after.
If you need anyone in the future, though, let me know. I only have 750 of the original 1,000 and bought the season pass on sale, so I need pretty much everything. Best of luck with the boosting tonight. Wish I could help!
I just got super lucky...went to go do my final mode, propaganda, start loading a match that is in game already...while in the loading screen achievement pops. It ended as I loaded and I was loaded enough to be counted as "in"...good riddance.