sure, Dick.... he stands where there is a line of people who are NOT armed, and fires rapidly, changing clips maybe once. If he picks the right place to position himself, he could shoot anyone trying to rush him for a minute or so. Many people who are being shot at try to get away first, not charge AT a guy with a gun. As it is, he only had about 2-3 minutes.
Maybe they will explain more how he actually did it soon.