Great class for avoiding boom?

It's different with every boss. Some of them use an hp trigger, some get harder if you kill them too fast, others if you don't kill them fast enough. It's hard to say really.

I think most classes can avoid the boom if they learn the triggers. Just alchemist have a larger variety of spells we can use. We are not stuck using the one hit wonder nor are we super worried about keeping up with buffs for sustained dmg/def. We run though our list of spells and see what works and what doesn't.

I know for me, if I can't kill it with a 200k blizzard or a 400k poison bomb, I gear up for anything the boss could throw at me until I memorized their pattern. Then Ill just take what I need to kill quickly without wasting to much spina on spells.

You can also stun the boss like assassin, but its only last for 10sec max. So assassin is one of the best job to avoid boom from boss that can be killed in under 10sec, like almas, oritius, mezza etc.