In 1965 he was sent to South Vietnam as an advisor to an Army of the Republic of Vietnam infantry regiment. He stepped on a land mine during a patrol and was evacuated to the United States. Doctors at Fort Sam Houston concluded he would never walk again and began preparing his medical discharge papers. As Benavidez noted in his 1981 MOH acceptance speech, stung by the diagnosis, as well as flag burnings and media criticism of the US military presence in Vietnam he saw on TV, he began an unsanctioned nightly training ritual in an attempt to redevelop his ability to walk.