my brain on this boss: it's Jotaro Kujo!
I'll be that guy.It was tanked on the wrong face, giving dps and the healer only one very small section of a safe side to hide themselves.In many cases doing this with the explosive box so close leads to multiple dps and the healer being pushed out by the exploding box and becoming no longer safe. In the case of the video the priest was smart enough to avoid the knockback but did not have time to get into the safe area. If you are a tank and this same situation occurs, it is still very possible to position the boss on the correct face/corner and still provide your group with two safe faces. Which will in most cases help your dps and healer avoid being knocked back.Alternatively if you tank it properly you will move the boss after venting flames so the next box does not drop right beside the one that is to explode. Avoiding this whole scenario and making it somewhat safer to pull this LoS trick off.
I came here expecting the mentioning of the Resonating Arrow, at least for Kyrian dudes. I save this for those venting flames cast on my SV Hunter, the first one I pop the Aspect of Eagle, for Raptor Strike/Mongoose Bite attacks, but even without it, KC and SS deal enough damage to diminish its health in those 10s (KC doesn't even need the hunter to be in LoS of the target, just the pet, which, if not imune to it, take very little damage from that).
It still is a very risky method, as on m+20 tyranical one single tick will kill you (at least currently with ~285).So while it obviously holds true that it does save quite some time, I would not want to use it unless you really want (and struggle) to push that key.
i know this priest hes kinda dumb.... it happens, but good content i liked the tutorial