Here in Ohio, most people will do things like help each other dig their cars out of snowbanks, because that's just what you *do*; the snow is a common enemy when everyone is trying to get somewhere.

And when there's a disaster, that tendency is magnified. When threatened, people want to help each other so instinctively that it feels completely natural to help a perfect stranger. The more obvious the problem is, the more you feel responsible for helping (especially if you are the only one there), and the more easily you can think of a way to help, the more likely you are to do something useful.

If Buck were a real person rather than a badly-written character, he absolutely would help out. Depending on his training, he could help administer first aid, commandeer a baggage cart as an ad hoc ambulance for those too hurt to walk, or simply grab the nearest struggling individual and help them to the terminal. And it would make for a great story afterwards, too.

When a crisis is huge and right in your face, people don't generally just walk away. They might not act at first; if they don't know what to do, they may stand there staring indecisively until someone figures things out and starts doing something or giving orders. At worst, they get confused and do stupid things trying to help, sometimes adding to the casualties. At best, they work together as though they'd been practicing for years. But they don't just walk away.

At the same time, I'm going to go with that only the "Trib Force" folk are sociopathic -- Rayford Steele makes a good villain, especially if his narrative causality makes NPCs automatically think he's as handsome, smart, etc. as he thinks he is -- but my experience with evangelical Christians is that they may believe strange things about biology or astronomy, but they're good people, by and large.