Michael Cornwell of Springfield, Ohio, thought he was going shopping the other week. Instead he ended up taking the kind of thrill ride that would make anyone's hair stand on end. It all started uneventfully enough in the parking lot of a Kmart outlet, where Cornwell, his fiancée, and his mother were headed. Things quickly got interesting, though, when two women ran out of the store with store employees in pursuit. Cornwell sensed what was happening and was not pleased. First, he planted himself in front of the shoplifters' getaway car and demanded they stop. When he stood his ground, the driver bumped him twice then floored it after he jumped on the hood. He clung desperately to the windshield wipers as the car hit speeds estimated at 70 to 80 m.p.h. Eventually the driver pulled into a mobile home park and the women fled, only to be arrested later on charges of assault and stealing perfume, cologne, and other items. In explanation of his determined crimefighting effort, Cornwell only said, "I don't believe in shoplifting."