There's a glitch when you get to the roof, at least in a hard-elite run now in the halloween event, you have to kill a pumpking tyrant to be able to still fight the aberrarion, the volatile would disappear and re-appear with a full healthbar, I tried so many times that I ran out of stuff to heal or do extra damage, so..... :[
#Pumpking tyrant glitch in tower raid
drifting coyote