Dot damage annihilate at 1k corruption/ubers

It’s just less than half a second, you just touch this uber abberoth void flame line ground and you instantly dead, even you play void knight with 4,2k hp, 1500 endurance and tones of fragility/less void damage taken/etc.
Same with poison on monolyths, i know that belt on cleanse is must have, but i don’t get it right, just cause can’t get even 2lp chains belt. So, without it i must use all 3 flask and it’s not enought against poison, and i still die.