I've noticed that I don't always take the exact same amount of damage from the same chest, even opened by the same person. I also try to stand as far away from the chest as possible before opening it. Sometimes it works best if you stand to one side, but it's always variable. So I save first, and if everyone dies I start again from my save point.You can also increase the Perception skill, as this is advertised as allowing a character to take less damage from traps when they do go off. Pushing Luck up couldn't hurt either.
