sentence: in prison , his life was spared at the insistence of roman karmen , the soviet propagandist who directed all the main sequences illustrating the battle , from the viet minh raising the red flag over general de castries 's bunker staged a few weeks after the siege , to the french union pow column marching from dien bien phu to the re-education camp ( a crane was used for the shooting ) , that are featured in вьетнам ( '' vietnam '' , 1955 ) .