"thats not a knife.....THIS is a knife"
Crocadile dundee

Only a fool would bring a knife to a fist fight

As a Airforce Security Forces I have to agree with N-T-Fan on this. if I have nothing at all to use for defense and somebody pulls a knife on me, Ill wait for backup before getting into a close range situation.
Though on the flip side if I reason to believe this knife wielding crazy will hurt another by my waiting Ill take him down by any means sense that is my job.
Probably what this guard was thinking at the time, If I do not stop him who knows what he will do.

awesome job promote him now !

I have been lucky enough to take down 2 edged weapon offenders using a baton.
In hindsight I was more stupid and lucky than skillful.
Nice to see the bystanders helped (not).
People with knives should be shot.

Noob Stabber...

This is from finland and he really had a knife and he pulled it out when shoplifting went wrong.