President Trump was born in 1946. This is when men were men, and not feminized like they are today. Today men are not men, but more like women. Women would prefer stay put with the children and wait for the men to arrive. The men of Trump's father's time, enlisted to fight Nazis and Japs. These were very formidable enemies who were taking over the world. One untrained shooter fighting unarmed civilians, compared to Nazi's, is called basic training.
Today, just words are enough to place the liberal brain on overload, requiring a safe spot to recuperate. The sound of a gun is not a PC sanctioned sound, so it is double scary. Each generation is projecting its own value system. Men of old were not afraid of words, so gun fire was something you could train for.
Running in, without a gun, would still allow one to draw fire away from the unarmed civilians. The shooter does not know if you have a weapon or not, so he will need to take care of that threat. This distraction gives more time for evacuation, before the cavalry arrives. If you lack a weapon, you need to be smart and not corner yourself. Instead, you look around, keep moving and try to set up an ambush with improvised weapons; special forces 1.0.
The word hero has been so watered down by PC, that now breaking a finger nail makes you a hero. Or if you walk a 5K walk for charity, that makes you a hero. Back in the day of men, hero meant valor under fire or duress. The standard was higher so threats were not as threatening.