We tried it today but seems next to impossible to acomplish. Made it on 25man hc but whiped on first try (idk if that ruins it all and have to kill it flawless on first attempt) but flawless on second attempt where I know that I didn't got hit by tornado or the blobs that the Intitates summon cus of the GTFO addon that didn't sound during the whole encounter and still the only I've got is the cloud which probably everyone got if they stay on the ground.
What I've heard is that it's an invidual achie so some can complete it and others not depending on if you're good at it or not. Or am I mistaken?
Or is it bugged somehow? Idk but this achievement creeps me out and have no idea what to do in order to get it done more than avoiding all shit...
Edit: Yes I stayed alive from start till the very end.