Any tips for accomplishing this then? My best guess would be standing in the starting area and luring them all into the doorways to try to get them all dead at the same time. And yes, I'm aware of giftdropping. I'll probably use my worn armor, since I'm otherwise all out of gifts at the moment. I was hoping it would be possible to accomplish in in some simpler way (I know, silly). There are plenty of sergeants, so I might just knock them into the lava. But still, even with the weapons gone, I think I never saw a corpse. I might just be missing something. If I saw corpses it'd be simple since I could blow up a decent chunk of it with my rocket launcher. It was just confusing since neither the wiki or the internet in general didn't answer any questions about respawning enemies and levels like CC+ that requires killing all enemies.
*Edit* Adding an attachment of a screenshot of my main position up to this point. The majority of the enemies are in a spawn/kill zone within my vision range, the main exception (which I noticed when doing a scouting mission) was one former human. And yes, picking the loot up on the spot of a dead former at this point certainly yielded a real corpse. Miss on my part. I'll be finishing this up for tonight, but thanks.
*Edit 2* Managed to take care of it by luring them all into one place aswell as putting a few of them into the lava with my Double shotty.