[Kawaii Sachi's Rant] Liam's motive: He remembers Gambino is his dad, he gets angry, and wants to kill Gambino
How he might be Gambino's son: He says he doesn't know his parents and has been on his own since 5. He has yellow hair like Gambino, and Gambino might have cast him away cause back then he as poor and didn't have enough money to support Liam.
How Liam did it if there was the other sniper: the sniper was not for Gambino, it was for Liam. Sniper=Edmund. Eddie is a friend of Gambino, and he hears about Liam so he goes there to kill Liam. Liam (Aekea) is closer to the tower than Eddie (Durem), so it would be easier to kill Gambino.
Facts and ideas: Liam can build bots and destroy them. Maybe he built the Easter Bunny, whose giant carrot is the sniper gun. The Easter eggs collected from us were explosives used to bomb the tower.
It's my screwed up theory. xP [/Kawaii Sachi's Rant]