I'm not sure if it would help or if it was pointed out in any Speedrunning Category, but I will still share it there, If you open your inventory quickly enough before a boss scream, you will get opportunity to move, attack, cast spells, without taking damage, maybe it would help getting quicker times during fights like Brooding Mawlek when speedrunning Pantheons, but I'm not sure.

This is an inventory scream skip, it's known about and banned from NMG runs

Oh okay, thank you for explaining

it also doesnt let you damage mawlek during scream so it wouldnt be useful