probably because they have bounties or other objectives that require to kill that wanted enemy, while others have bounties that require that or any heroic event completed, just take a break, then once your jets are cooled, try again, what I usually do is run warlock, (it's my only guardian that 600+ light level) if not, see if somebody else can use a healing rift to keep you alive while the cryo fluid is out, and don't bother with the adds, just get the orbs, and throw them where ever needed, but if you fail that time too, just take another break for focus on something else on D2, I'm trying to get the mountaintop but I keep fluctuating between guardian 1-3 because my teammates keep rusing in and dying one by one while the opponents are packed like a school of sardines, I'm gonna get there eventually and I'm sure you will too cheers!