Jeff Smith was pulling a stump from his garden near McDowell Creek Park on Monday, but his mud-caked boot slipped off the tractor’s clutch. The machine flipped upside down and on top of him. The steering wheel pinned the 36-year-old to the dirt, pressing into his chest. He yelled for help. “I was losing more and more breath every time I screamed,” he said. His daughters, just home from school, were walking the family’s dogs. “We heard, ‘Save me. Help me, God,’” said 14-year-old Haylee Smith, an eighth-grader at Hamilton Creek School. She and her sister Hannah Smith, a 16-year-old...