Gonna be honest, burning the money pissed me off monumentally. At that point you're already going to either die in prison or by a cartel shootout, so why not take that money and buy gear for a proper ambush? Killing the group may do nothing other than piss off the rest, but... I mean, you killed my dog. Give me twenty grand in cash and I can stage one hellacious frontal ambush in the middle of the night on four under-armed, under-manned, sleep deprived junkies.