if you mean "really safe and really ready"
no, it's not fast.
let's run down a scenario.
parking garage, GF is walking to the car.
she sees a strange looking dude walking toward her. he is closing. She may make it to the car w/o running but can't get in in time get inside and lock the door. so she put's her hand in he purse. and keeps walking. perp keeps closing, she glances back and he put's his hand in his jacket pocket and takes hold of something. as she makes it to the door, he is at the back bumper and says "i'm going to f.ck you up b.tch!". she pops the lock and activates her car alarm. she draws the "weapon" and turns and points it at him.
he looks stunned for a minute and then grins, pulls a knife and says "your not going to shoot me" and lunges at her. she can fire the pistol, spray him with CS or try to unlock a pistol with a little key she has on her key ring. she is scared, shaking and not really ready for this. it's a bad deal but that's life. so she get's one or two rounds off with the .38 or a quick spray with CS maybe she drops him maybe not. either way he is at her feet and she must retreat to the front of the car to call 911 on her cell phone. she may have to shoot or spray again.
just saying I have tried to use these locks under stress and they are very Very difficult to make work.
you can make an argument for putting both hands in the purse on the way to the car or brandishing a weapon on the way to the car but the first will leave you vulnerable while you are walking and the latter is illegal.