years ago a deputy was sitting in a sambo's restaurant with his back to the front door. guy comes in intending on shooting his wife further back. so he puts a round in the back of the deputies head prior to taking out his wife.
to this day i won't sit in a restaurant unless my back is to a wall, and i have clear view of the traffic in the restaurant. usually there is a fanny pack sitting by me on the bench seat with ready access.
In thinking about it tho, i have always preferred some type of holster, rather than having to dig one out of a pocket.
Gosh, didn't the guy learn anything from watching 1960s TV westerns. Marshal Dillon never sat with his back to the door. And neither have I.