My Spirtdancer started killing herself when using a phase skill. I think I figured it out, it only happens when my character would normally rephase itself and only with the "Phase Mastery" skill. I used a respec potion and without that skill my character doesn't die for no reason anymore. Also, I don't think the dancers are giving my character any elemental resistances. There are those levels with fire environmental damage which didn't hurt less when i was dancing.