There's a weird interaction between the Quellor and Magus Lockdown. I've tested it with other weapons, doesn't seem to happen with them.
When an enemy is "magus-lockdowned", it will occasionally take *MASSIVE* damage from one of the regular rapid fire Quellor bullets... and when I say massive damage, i mean like half of a lvl 160 heavy gunner's health.
First, i didn't think the "unaware" state applied to guns. Even if it does, it's only the occasional bullet, not all of them.
It's not related to head shots, and i can't figure out if it's related to crits, or maybe status procs... don't think so tho... and it's not every bullet. just.. once in a while. You'll be shooting it for small amounts of damage.. and then seemingly randomly... BAM! half of the health bar vanishes.
Hope this helps.