what the hell dom was thinking? so lame

How could dom turn his back on his family like that? that was so effin lame that he agreed to betray his so called family team and put the whole world on nukes JUST for the woman he thought is dead and the son he never saw before or had feelings. wtf He shot them, tried to kill them in the best possible way lol didn't make any sense.
Story was totally flat and lame but Ok for its pop corn fans