Imagination. Dice rolls make me want to die. 

Basically, NPC's, even the grunts, will be treated as if they were player characters (at least, relative to the players). I'll be moving them around, having them search around for you ect. If you want to kill an enemy you just treat it as if you were attacking another player in any random role-play, rather than killing them outright in your post. I'll then write them out getting killed or managing to escape.