There is no defense against a surprise attack of unarmed civilians. That's why it's called terrorism.
It doesn't matter if it's guns, knives, bombs, or sharpened pointy sticks.
If you're the closest to the attackers when they start killing and didn't notice they were doing something weird, you're dead. It's that simple.
Further away, there's a short timeframe where there's usually options.
Acting surprised that it occurs at the most insecure and disarmed places in society is silly.
Blaming good people who would prefer to be in those places armed, as if they're the problem, is even sillier.
Sending a largely poorly trained and ill equipped police force to respond to terrorists, even more so.
(Most police forces don't have the budget to train properly for urban warfare, and that's what terrorism is. The elite/special units do, but they're 30 minutes out from any event like this and that... Is exactly what we vote to pay for. Ask any beat cop how many scenario based training sessions they get per year. Ask them if they think that's enough for them to be ready for one. The answer may surprise you. )
The idea that armed good people that have a sheepdog mentality would screw up so badly that everyone would die, is also ludicrous. Hell, if nothing at all else, they'll be a great distraction for the bad guys while you slip out the back door. At best, they'll stop the threat and save your life.
Reality will probably fall somewhere in between, and lean toward the better outcome more than the worst case, since at least one might understand they also need to mount a quick and vicious retaliation in order to maintain their own surprise advantage.
There's a whole lot of delusions about security in rich societies in general.
People don't realize it's what they eat that will kill them, long before a terrorist darkens their doorstep.
And it'll be someone who wants you personally dead who'll darken them doorstep long before a terrorist crosses their path, too...
...if we are going to remove self-inflicted damage from the discussion.
And it'll be an idiot texting and driving, that kills you, long long long before that.
Now back to the original question. What can you do?
If you must attend large gatherings at locations where everyone supposedly will be disarmed, pay a little more attention to your surroundings. Know where the exits are and know what people are doing around you.
There were reports of people in the theatre who had to bodily throw others up onto the stage because they knew there were exits there and the idiots were frozen and standing in the way.
Situational awareness, self defense trainers call it. Paying some ****ing attention is what my dad called it. Either one works as a description if it gets you to do it.
Henning, when talking about pilots and not social engineering babble, has mentioned before the concept of "freezers" and people who "act".
While he believes it's mostly genetic, and science may yet prove him right, I believe that people can behave differently when shown how.
Ask any beat cop if it's a foot race in their group as to who gets the furthest seat from the main entrance door, their back to a wall, and their strong side / pistol side outward in the booth or chair when they go to lunch.
Now also ask them, when they lose that foot race, if they mind that the guy or gal who has the best marksmanship of their group, ended up in that seat.
It's both an individual function and a group function. If you have people with you who will literally watch your back, that's a good as you doing it. (Ask any politician with an armed security detail.)
Even if you're not willing to give up your "party scene" and want to be a drinker and paying no attention at a concert or similar, invite friends who pay attention.
This isn't rocket science. Friends do this type of thing all the time for drunk friends. Making sure they don't get in too much trouble. Being their eyes and ears when someone is hitting on them in a compromised state. Etc.
If in venues that allow people to not be arbitrarily disarmed, take a "gun nut" along that you know. Or a friend who's a cop. And don't ask them if they're carrying. Maybe they are, maybe they aren't. Just let them be. That's their call. You have your own choice and free will in the matter. If you chose not to, that's your business. If they chose to, that's their business.
If they are carrying, they'll probably look out for your sorry ass, when they really don't have any legal obligation to do so in any way.
Scoff at Doc's commentary as gung-ho all you like. He's your best friend when the shooting starts.
Of course he may have decided with our legal and liability scenario in the U.S., that even though he's willing to "drop the bad guy" -- if he can get to safety, you're on your own.
He wouldn't want any of the whiners here, suing him out of house and home, if he happened to miss.
And as others have mentioned, even without firearms involved at all, you want a buddy who's just stupid/brave enough to try to stop bad people. Those who will do it without hesitation or complaint are worth their weight in gold as friends.
Very few people run toward trouble. They usually have to be acclimatized to it and trained to do it. Police, firefighters, EMTs, military, and all variants of retirees from those types of professions usually do. They've been trained to take cover if needed, assess, and move out toward their best option.
Whether that gets them a block away, panting and thankful they knew where the exit was, and they hit it immediately at the first sign of trouble, or if it gets them dead rushing an attacker to save others, or something in between, really isn't much difference in their thought process. They're going to act.
That friend you know who stands straight up and looks around like a prairie dog every time there's trouble? Yeah, he's gonna get his head blown off in a terrorist attack. Poor guy.
If you're near him, either drag his ass down to the floor or let him go up and be a target. Your call. Because he always does it. We all have one of these friends.
Those who are not acclimatized to bad situations are probably going to hit the floor and then may or may not freak out. Wildcard. Some people switch into survival mode and do well. Others attract attention to themselves and die.
The funniest thing in the thread so far is the firecracker comment. It does pay to know what the hell gunfire sounds like versus a firecracker. Many people do. Far more don't. The likelihood that someone carrying a firearm doesn't, is pretty damned low.
Anyone else notice the beat cops weren't holstered last night. That was the one that got me. Not a one in the early footage had their pistol holstered. All were out and held near the chest. If you don't notice such things, start. If you see beat cops doing that, even the ones blocks away from the scene handling crowd control duty at the press line, some serious **** is going down. Real serious. And they haven't caught the bad guys yet.
It's little things like that you have to teach yourself to notice. Well I say little things, but if you're thinking about it, that's not a little thing at all. Seeing every cop in a multi-block radius drawn and not holstered, isn't little at all. But many people would easily not notice that. At all. They're too inward focused to pay that much attention to their surroundings.
That's all I've got. There's whole classes on this stuff and they don't even have to be firearms related. They're not expensive or even hard to find. If your question is serious: How? Then go find out. It's not a secret.