Making lots of targets also helps. If you have a point in skeletal wall, spray those guys out. Skeletal wall takes much less spell casting time than Shield does, and enemies always change their focus to the newly arrived skeletons. Sure, they'll drop dead in the first few seconds of hell spiking, but they're so spread out, it'll take 2-3 casts to kill all 5. Then you just summon s'more.
If you have a ranged weapon, drink a shadow potion/hide and snipe from afar, while producing mob after mob of skelefodder.
