If it wasn't for unavoidable damage aka choreographed you could absolutely do this. There is a reason many first kills take place with 1 less healer than a standard kill will have. For example Method ran 2 healers on their queen kill because they needed every scrap of damage and they could trust their players to not take random damage. There is a reason top guilds consistently try to cut down on healers needed it's because damage is what matters unless you are bad and stand in damage. Let me guess you are someone who think corrupted viscera was just damage the healers needed to deal with instead of moving out of it.
If you think that standing in bad is fine you are the one who hasn't raided at a challenging level there is a reason that failure damage is a stat.
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So I have an honest question because I honestly don't get it how can you play a game for hours a week possibly tens of hours a week without wanting to have the best performance you can have. Like I get it for people who just use it as an rp tool but for people who actually play the game how can you not want to experiment and do the best you can it doesn't actually make sense to me.