...I don't think a mall cop should be carrying a ****ing firearm, nor should he be going for a killing shot- shoulder/leg at MOST.
The only thing this kind of thinking validates is that the person advocating it knows nothing about firearms.
--It's one thing to call your shot when you're calm, at rest, and aiming at a fixed target at 7 yards, which statistically is a realistic range for a defensive shooting. Not the same when you AND the bad guy(s) are probably moving, the distance might be greater than 7 yards, you're being shot at, your heart rate is significantly elevated, and you're experiencing an adrenaline dump resulting in your fine motor skills going down the toilet. Just as with any type of physical skill, (sports, playing a musical instrument, etc) your proficiency goes down significantly if you have to perform under stress. You might be an outstanding shot at the range, but under the conditions above, unless you train extensively, it's a different story.
--Even if you were lucky and/or skilled enough to make a shoulder/leg shot in a defensive situation, you do realize that your target could just as easily bleed to death, right? Hit the femoral artery in the leg or the subclavian/brachial artery in the upper arm/shoulder and the bad guy is in pretty bad shape.
--Police officers and responsible armed civilians are trained to shoot to stop the threat. This generally means aiming for Center of Mass (CoM), and continuing to shoot until the threat is neutralized. CoM provides a relatively large and quickly identifiable target area to aim for, and contains the vital organs. Neutralizing the threat means just what it says - if someone is shooting at you or charging you with a knife, you shoot until the threat is gone. And in many cases it can take more than just one or two shots, unlike what you see in the movies, before the threat is neutralized.
It's silly and unrealistic to think shooting out a leg or arm when the other person is shooting at you is a good idea or an effective means of defending yourself.
I'm still not comfortable with a mall cop carrying lethal force....there are plenty of less-than-lethal options out there.
--If you live in the United States, chances are you probably live in a jurisdiction that allows for the legal carrying of concealed firearms by responsible civilians who have undergone an extensive background check in most cases. There are only a handful of states that DON'T allow for this. So if you're implying that a mall cop is not responsible enough, insufficiently trained, etc etc, to carry a firearm, just remember it's just not the mall cop who may have lethal force at his/her disposal. For all you know, the mall cop might be a real cop moonlighting as private security. And despite this, we don't have shootouts on every street corner. Hundreds of thousands of law abiding civilians go about their daily business with a legally concealed weapon and do so responsibly.
--Finally, less-than-lethal means less-effective. Tasers and pepper spray have a limited range, don't always neutralize the target, and you'd better hit what you're aiming at with the first shot because that's all you might have before running out of pepper spray or having to reload a fresh taser cartridge. If you're going to engage with martial arts, you'd better be in pretty damn good shape, have years and years of training, and be able to get within arm's length of your assailant. If someone is shooting at you with a gun however, I think you'd be pretty stupid and overly confident to engage with a "less-than-lethal" means of force.