One good tip is to remember that many NPCs will offer concessions if they're clearly being beaten, especially if they've gotten roughed up a bit already. Heck, any NPC who has taken a moderate consequence without doing any real damage to his opponents is probably squirrelly enough at that point to turn tail, no matter how maximum their power could theoretically be. First session in my current campaign featured extreme, brutal, bonecrunching violence since none of the NPCs conceded conflicts, instead attempting to flee via actions. Obviously we ran them down and broke them, of course.
Basically, Concessions are magic, because it lets the NPCs get off a little bit easier than having their torso shattered.