Hardcore got nuked by something

I think I just got nuked by the mines in Plains of Strife, but not sure. Literally stepped out in the plains and dead. Everything else had been quite easy.. Other characters I've never had this problem, even through multiple difficulties. What am I missing? How do I prepare for this? Fire resistance maxed or something more is needed? Also is there something that could help me not get nuked by anything else in the future? Like is there a relic/devotion or something that could save you from one-shots?