What I have absolutely no use for is the despicable coward that is too squeamish to provide for his own (or his family's) defense and expects someone else to put themselves in danger for them.
This is where I differentiate between the police and an armed citizen. A policeman has chosen his profession to serve and protect (at least on the societal level). In the scenario above, he should engage the shooter. It is his job. Speaking as an armed citizen, if there is a way that I can get out of the situation without engaging the shooter, I will. I am under no legal obligation (although there may be a moral one) to defend those that will not defend themselves. If I cannot get out of the situation, or if I am presented with a shot that does not endanger myself or those that I am bound to protect, I will engage the shooter with my own weapons.
I may have misunderstood you, Punch. Are you saying that those who do not arm themselves are "despicable coward(s)" who put their defense in others' hands? If that is so, I most violently disagree. There is no moral imperative for anyone in civilian life to walk around armed. While the carrying of arms by civilians is, under certain circumstances, legal and can be, conditionally, useful if a certain scenario presents itself, to call those who go unarmed cowards reflects a very skewed understanding. Perhaps that is not what you meant. If so, then I apologize.
It seems to me that, were you in a situation with a shooter, you, as an armed citizen, who have taken upon yourself a means of protection via a weapon, are now responsible, after taking care of your family, to deal with the shooter. If you just avoided him, THAT would be cowardice, because you potentially left people to die so you could escape with your life.
Those who choose not to carry weapons cannot outright be called cowards based on that decision alone, nor can they be treated as inferior to those who do choose to carry weapons. What separates the brave from the cowardly are the decisions made in that critical moment. At that juncture, an unarmed man who confronts an armed one, especially in order to save others, is far braver than an armed one who confronts a killer with a weapon.
Armed or not, though, it all makes very little difference in terms of bravery, cowardice, or morality. Somehow, we tend to see victims as helpless. Are we so blind to our Christian faith? Was the Lord helpless? Were the saints? Surely not! The Lord and the martyrs showed their strength, bravery, and manliness in enduring suffering and death. Other saints were killed in another way, but ultimately for the same purpose, in protection of the defenseless. Has their sacrifice been wasted? Were the defenseless at fault because they did not fight for themselves? No way.
For some reason, we like to dwell on hypothetical situations. I guess there's not much for it. But the real substance of these things lies in what actually happens--what people do with the circumstances. I don't think we can see the whole picture--only God can.
Say that crowd in the situation of the OP comes together, rushes the lone gunman and tears him apart limb from limb. Would they be justified? I think you will find little support for this in the Synaxaria. Likewise, say everyone in the crowd decided to sit still and allow the gunman to shoot them all. Are they they to be condemned as cowards? Likewise, I think you will find little support for this. However, in the all too many scenarios enacted all too frequently, the crowd never speaks with one voice and act. Each individual's action and witness is different and based on what God has given him or her. Identified and fixed the cause of the strikethrough problem. You typed the "[ s ]" combination (sans spaces) in one spot, which the parser read as html code for the beginning of a strikethrough block. I replaced it with the combination "(s)". - PtA