If your hypothesis is that TSA agents are incompetent or careless or otherwise malign, then every extra moment you spend in their presence puts you at risk of the kind of things that such people might do. TSA agents have been known to assault people. Rare, but more common than injury caused by scanners.
Or just get sick from close contact with another human being. Influenza and Covid-19 can be serious! Probably much greater risk there than from somehow accidentally getting boiled alive by radio waves from a scanner.
