Last night in our game, my character as squad leader rather impetuously threw a grenade into a room that had been described as 'foul smelling'. I don't usually do this, but I just *assumed* there were more cultists, since we'd just killed about 300 of them. Turns out, there were two teenagers that I'd killed. Confirming whether or not they were cultists, I..er...nibbled one to see if I could determine this. They were, in fact, completely innocent. I kind of felt bad about this since a) they were innocent civilians and b) it was a waste of a grenade.
What do you think I should do (or what should the DM do...he's not sure either)?

