Robert Stethem lived 10 minutes after the U.S. Navy diver was shot by hijackers of a TWA jetliner, a doctor testified Tuesday in Frankfurt, West Germany. Dr. Michael Clark told the air piracy and murder trial of Mohammed Ali Hamadi that he performed an autopsy on Stethem's body in 1986 at the request of the FBI. Hamadi, a Lebanese Shiite Moslem, is accused in the June 1985 hijacking in which Stethem was killed and 39 Americans were held captive for 17 days.