Help me not die in tier 15 maps

I wasn't getting killed before starting to juice the maps (not going overboard), like for example right now I've clear the Savannah map (shit map btw, negative fps). And after clearing the map I thought i'd try out the breach .. fucking slideshow I tried stampeding from end to even to clear trash mobs to regain health but it was just too much and I died again. I'm a level 89 Titan warrior. maxed out the resistances obviously and the modifiers on the map weren't too punishg IIRC (13% reduced resistances, 36% extra lighting damage for mobs and two good modifiers)