Thought this was common knowledge, it even tells you on the screen but I guess not. Can you please roll to the side after Poseidon blast you with water. Do not stand there and let him continue to spray you with water. I can't count on how many times I've seen this happen. I've seen healers try to heal through it, I've seen dps stand there and not roll hoping the healer heals them through. Not even sure a tank could survive, even they did because they have a better chance of surviving. Able to pick you up is no guarantee, Poseidon likes to drop the pool of water right as a down player is being revive.