Last Platoon (1988)

After ex-cop and highly decorated war hero Chet Costa's Vietnamese girlfriend disappears, he accepts a risky mission: he shall blow up a bridge at the Vietnamese border to close the Vietcong's line of communication. He's given a group of prisoners to accompany him. Already on the way there their helicopter is shot down; a march through the wilderness begins. When his soldiers recognize that they're effectively on a suicide mission, they decide to get rid of their Sergeant and to flee to Bangkok.