 Some did not survive the forced exodus to the countryside where they were expected to work in the fields.Rockoff tried to forge a passport for Dith Pran using an old passport belonging to Jon Swain.He is incensed at the way the 'Killing Fields' movie portrayed this, particularly scenes which appear to show him fixing up an improvised dark room and chemical solution while a photo of Pran fades away, until he finally gets it.