What happened to the plane when the bomb detonated?

Once the plane took off from London Heathrow Airport and once it was in the air the bomb had detonated. this caused a hole to rupture in the cargo area this hole enlarged within seconds and the side of the plane had been completely ripped off and then the top of the plane had followed, then the cockpit
broke off and  to the ground and landed in a field in Lockerbie, the rest of the plane rained down the town of Lockerbie killing people and destroying houses, a huge  crater had been made by the back end of the plane falling down, when the engines hit the ground fuel was everywhere and huge fires were started which took hours to put out. once the cockpit had been recovered the flight recorders had been retrieved and all the information taken out of them and analysed, the information had shown that it was not a pilot error and not a mechanical failure but something that had happened almost at the speed of light, and there was a shockwave that had come from the cargo holding area.              

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.