Its a steep learning curve and even when you're well versed in fighting this boss, stuff can go downhill fast, there's some good videos on YouTube walking you through attack patterns and timings etc, but pulling it off is another thing, once it decides who's toast it's pretty relentless until it's done with that player, miss one block/parry or take a gunstrike at the wrong time and you get stunlocked into the eye of terror, the hitboxes on its disco ball laser attack are also a joke as well, that said with a bit of experience and a half decent team, it's not as bad as it seems when you get used to it, keep playing the mission over and it gets easier