Are there no store exit doors? At malls here, most stores have outer service doors. They aren't really noticable but there.
I sincerely doubt I'd be thinking about running around to find an exit door when suspects running around and shooting random people.
I was just guessing like everyone else. Some outside doors require manager's password (to prevent employee theft)...some back doors just lead to hall ways which lead to the individual stores' service doors. I was just replying to one FReeper's bravado of how, in such a situation, he would fight anyone who even suggested he take cover in backroom. That is how we got on the topic of egress from mall stores.