Responses
They wanted not only to kill him, but to erase all knowledge and proof of his existence - if they just shot him, someone could find his body etc, like it happened with professor Midokawa. This way he would be completely destroyed with island and no one would think to sreach for a body on abandoned island. At least that's how I understand it.
Oh i see i see. You're right, now that i think about it.
There's something i don't understand, i must've missed it... But if those organizations want Akira dead they could easily just shot him down or something, why go through all the trouble of blowing up an island???