how does an 88 yr old man carry a shotgun thru the Washington Mall and security didn't catch him?

they are busy

Even if the shooter went through the mall, mall security does not have the tools, equipment or training to stop/apprehend him. I work as a mall security officer, and believe me when i say that mall security is a complete joke. Their are to many restrictions in this field in regards to with what you can't do, which is pretty much everything.Let's not forget the lousy pay. If all 50 states don't give private security "special police" powers, and better pay/train their workers, there really is nothing security can do. All you can do is hope and pray the police arrives on time to stop the shooter. But even by then many lives would most likely be lost. The reason places like malls, don't grant security more authority or upgrade security is because of liability concerns. Mall management could care less about the safety of mall patrons, as long as their not getting sued. Remember malls are a place of business, they could care less about anyone's safety, which too me is wrong

By driving his car right up to the front door of the museum.

He parked his car in the street right outside the entrance. I guess Fox didn't show this.