I think he rode up behind her and hit her with the helmet knocking her off the bike. The helmet and sunglasses went flying off. And then she fought him. The bike had no damage, so he didn't hit her with his bike.They teach you in self defense class never to let your attacker take you to a second location. So I'm hoping that too.
He probably intended to go back, but the search was already on. He underestimated how quickly they would respond.