To be honest, it's not as if M4 hadn't previously attacked Zexy... although in fairness, he'd just switched into the area where she'd already been Rollouting her other teammate into the ground.



Personally, my headcanon is that Zexy, and the other two Hoenn starters, had originally been a plant by Bill to monitor the crazy new Host that was claimed to be a child murderer and was roaming free. And in order to get one of his agents into Camilla A. Slash's hands, Bill hired a Zigzagoon to attack Professor Birch while he was carrying those three Pokemon that Bill had conveniently sent him.



Zexy's return to Bill was supposed to be as uneventful as Trapinch's, but a certain Ninjask named Dottie got in the way... so Bill got in the way of the Ninjask.



That's my story, and I'm sticking to it.