I was actually in the store when a crazy had a knife - we were warned and told to get behind the counter - which was very small. That was very scary. If one was armed and a shooter showed up at least you might have a chance. Perhaps the easy target Walmart should have had proper security to protect their customers - sure the crazy would have gone off on the innocent people but it could have been curtailed and many lives saved.
It's like shopping in Rio these days - people are robbed right in the malls, stores.