At the end of Act 3 of Path of Exile, there is a boss that causes the sky to rain blood (or something that looks much like blood -- perhaps strawberry jam?) This dealt considerable damage over time to my Duelist despite quenching my thirst with a flask of healing. This killed him. Luckily he was not a hardcore character and I was able to respawn after the rain stopped.
However, I'm now playing a hardcore character. I would really like to know how to deal with that blood rain attack by the Act 3 finale boss. Is that attack avoidable in some fashion?