On August 11, 1967, Wheat and two other Marines were assigned to provide security for a Navy construction battalion crane and crew operating along Liberty Road in Dien Ban District, Quảng Nam Province. After setting up in the tree line adjacent to the work site, Wheat searched the surrounding area for guerrilla fighters. He had returned to within of the security post when he triggered a well-concealed bounding mine. Hearing the distinctive hiss of the mine's fuse, Wheat shouted a warning to his two fellow Marines and then threw himself on the device, smothering its blast with his body. He was killed in the ensuing explosion. For this act, he was awarded the Medal of Honor.