Garrett Scott’s video documentary begins with a 1995 incident in which Shawn Nelson, an unemployed man in suburban Clairemont, California, drove to a nearby National Guard armory, hijacked a tank, and drove around the streets crushing cars until the vehicle got stuck and he was shot down by police. Scott tries to unravel the sociological causes behind the tragedy: the middle class had lost ground in recent years, and Clairemont had reached the end of its “useful life,” as one commentator puts it, when the neighboring defense plants closed down. But personal factors are equally persuasive: Nelson was on methamphetamines and might have been mentally ill (he’d spent months digging for gold in his backyard). Or maybe, as the helicopter footage of his car-crushing expedition suggests, he’d simply found a fun way to go out; even his brother describes the tank ride as “cool . . . something I would have liked to have done.” 55 min.