 On March 21, 1967, he was working as an advisor to a Civilian Irregular Defense Group battalion in Đôn Luân district, Phuoc Long Province, when a Viet Cong sniper was captured.As Hosking prepared to transport the prisoner to base camp, the man grabbed a hand grenade from Hosking's belt, armed it, and ran towards the 4-man company command group.Hosking tackled the prisoner and held him to the ground, using the prisoner's body and his own to shield others from the grenade blast.