Why was Al-Megrahi not killed in the crash?

Why was Al-Meghrahi not killed in the crash when the bomb detonated?  Al-Megrahi checked in the luggage and once he had done that he him self went and then check into another flight, this sent the luggage on the Pan Am flight and and Al-megrahi on a different flight. once Al-megrahi landed at his destination he would be walking away from the death of hundreds people and the death of an American dream. and once he was at his home in Tripoli nobody would know that he had caused this crash.