In pretty much all those cases, the rescuer wasn't in the building at the time. They "happened on"....two cops went to their personal vehicles and got their guns (note that they were two trained police officers). Others saw a man coming....locked the doors and were ready with their own personal weapon. So the moral of the story is....when dining in a restaurant, always hold your gun in your shooting hand and learn to eat with your other hand so that when you are in a situation where there is an element of surprise...you'll be ready to shoot.