Got me thinking that you need a 37mm flare launcher for your PF9. That way you got 2 minutes to run while the zombies watch the parachute flare drop...
Oh, man, all sorts of bad.
The real issue here is when you can leave the situation and when you cannot. A flash mob at the mall is an easy leave, evade, disappear. A flash mob in your store is another thing entirely. A flash mob in your front yard with you and the kids inside....
Had best stay the heck away from my house. If I cannot evade, defense may be my only option. In that case, I sincerely hope that they will break quickly, because I will not.