No, no worries, only the cops had the guns, as this is New Jersey after all. So obviously there were no firearms accidents. Oh, wait... Nevermind."We were a little bit nervous for a little bit that maybe there was something going on and someone was running around with a gun so we all came back inside," Harris said.
As for your title question, there is not enough information. Hell, there is hardly any information on how it happened to even guess as to why.