But is it genre? I could imagine Xena & Gabby giving some refugees tips on using a sling, and then one of them, in one quick cut in one fight scene, takes out a minor bad guy with a sling stone.If the PCs are accompanied by some townsfolk they've rescued from the gnoll invasion, I don't think that the mechanics dictate that a townsfolk could take out a gnoll minion with one hit. That's just silly.
But, anyway, Gnoll minions? There's two in the Compendium, at 8th & 12th, and minionizing standard Standard Gnolls would yield you 13+ level minions. Townsfolk'd be very low-level minions, examples like 'Human Slave' 1st, Borovian Commoner 2nd, Harkenwold Bystander 1st, Human Rabble 2nd. So, hitting a Gnoll minion would be quite the stroke of luck for one of those guys.