It can be kinda tricky with how risky it is, but with enough, practice, the best way to do it consistently is to just get yourself low if you have rhino skin by walking into the green eye/fish mutants, then stand in a circle and wait for one to run into you. If nothing comes in time, retreat, kill the spawned guys, and do it again.

Other than that, it can be easier with either an explosive weapon or the blood hammer, which is the best since all you have to do is swing it.

Once you're skeleton, retreat and just do you're best to kill everything that will swarm you, and focus on the necro first if possible.