Did the dispatch tell the cop only one 911 call was placed?
Did the officers encounter other people before they saw the suspect.
Do all citizens panic? For that matter, do people behave like they are always aware of their surroundings - take for example the subway crowd that the one nutcase pointed guns at while they were too busy on their mobile devices to notice.
In a vacuum, I would have been predisposed by wondering, given the 911 call of man with gun in walmart, why he hadn't shot any one yet, given response times and all and figured he had a screw loose and was waiting for cops - rather than deduce that an unboxed weapon was laying around and he just picked it up and walked casually around the store not getting other items to purchase.
