Good point in your last sentence. Bomb placed in the rear of the cockpit, under a jump seat or something which also impacted bathroom. Ground crew a possibility, anyone with access to cockpit. Right side cockpit windows getting blown out took a brunt of the explosion as well as disabling flight controls.
There is another point.
Why would a captain or first officer run the risk of getting caught with a bomb in his possession by airport security when he does not need a bomb.
This was done by someone who had no ability to directly control the aircraft.
Pilots know well how easy it is to crash an airplane.
I spent many years trying to prevent crashing!
A little slow and short on landing....dip a wing during the flare...hot and fast landings too far down the runway...set the altitude hold on the wrong number...takeoff on the wrong tank...there must be a hundred ways to crash without risking getting caught with a bomb.
Is the bathroom behind the gentleman seated in the jumpseat? I think the bomb was placed somewhere in this cockpit area;