The commandos parachute into Burma. Warden is wounded in an encounter with a Japanese patrol and has to be carried on a litter. He, Shears, and Joyce reach the river in time with the assistance of Siamese women bearers and their village chief, Khun Yai. Under cover of darkness, Shears and Joyce plant explosives on the bridge towers. A train carrying important dignitaries and soldiers is scheduled to be the first to cross the bridge the following day, and Warden's goal is to destroy both. By daybreak the river level has dropped, exposing the wire connecting the explosives to the detonator. Nicholson spots the wire and brings it to Saito's attention. As the train approaches, they hurry down to the riverbank to investigate. Joyce, manning the detonator, breaks cover and stabs Saito to death. Nicholson yells for help, while attempting to stop Joyce from reaching the detonator. When Joyce is mortally wounded by Japanese fire, Shears comes to assist, but is himself shot. Recognising the dying Shears, Nicholson exclaims, "What have I done?"