Malevolence Shrugged

I completed a T5 today with all challenges active, didn't destroy any obelisks, and didn't get this achievement, so not sure what I did wrong, the mini boss was horrendous so kinda salty I went through all that to not get the ach >.<

Completed this achievement today as a 269 hunter. Enabled tendrils, manifestations, malevolent boons, and tainted corpses to ensure I had pathways without a lot of extra mobs to just run to the mini-bosses. I did die twice to just not paying attention at the wrong moments. The squid had 4 debuffs, 3 of which were obelisk related. Once killed, the end boss had no buffs - killed her and got the achievement.

I've only tried tier 4 assault on the first day and got my ass handed to me by the next to last floating head mini-boss.
It empowered by 3 of those obelisks and is absolutely hateful mf when they are not destroyed.
I can only imagine what it's like at tier 5 and i'm ilvl 278

I guess this one should be much more easy in the group