Often you only need one round to deal with a mob - if they believe you have more they don’t stick around to be the next. Take out the leader and the rest scatter, it’s practically physics - you need trained, battle-hardened troops to get a different reaction from a group.
the cops in the mob may, in effect, be considered ‘trained troops’
What if up to 6 members of the group are trained police officers/prison guards...who may shoot back?