I can just picture the scene, Patrick:  Santiago pulls his pistol out of his waistband and starts firing.  In response, concealed carry citizen #1 draws his weapon and returns fire.  Soon after that, concealed carry citizens 2, 3 and 4, who took cover after hearing the first shots pull their weapons and look for the source of the attack.  Some of them zero in on Santiago, others on citizen 1.  Moments later the police arrive and see 5 or 6 citizens involved in a gun battle and many dead bystanders on the floor, so they all draw their weapons and begin firing.  End result, several dozen dead and wounded, and we all look back nostalgically on the days when most crazed gunmen could only kill a half dozen people in an attack.