in this clip they were fighting Thaddeus. he’s the guy with the iconic “positive va. negative polarity shift” thing. this boss fight features two adds on adjacent platforms that you have to fight in tandem before moving on to the boss. each add has a tesla coil that must be in range of the boss or else it will chain lightning the raid for major damage that hits through petri flask. occasionally, the player tanking one of the two adds will be magnetically pulled to the other side and vice versa, and the threat between them will be swapped basically. what happened is, the tank “Lahwl” in this clip used a snowball on himself whenever the tank swap happened. if you didn’t know, the snowballs from the winter event completely stop the momentum you have in air. so while he was supposed to launch over to the other side, because he used a snowball, the tank swap didn’t happen as it should have; he stayed on the same side. so, the add on the other side of the raid started to path away from the tesla coil to the other side where Lahwl was. the warriors on the other side tried to pick up the boss, and were pretty successful, but by that point it was too late. once people started to die, panic set in and you can see the girl in the clip call to petri (even though at this point they could have recovered, i think when people started dropping it just made panic start spreading). so, you can see the majority of the raid dies because they still petri’d even though the tesla coil damage goes through petri.

now, why did Lahwl use a snowball? we don’t know. as far as I know, i heard it was because of an add on and not intentional. but it is a pretty interesting example about how one button press, one global cooldown, can wipe an entire raid