His attempt to grab the Joker was impeded by the knife sinking into his arm. He sucked in a hiss of air, though didn't scream. He reached for his utility belt, grabbing a batarang from a pouch. He tried to use the instrument like a knife since there wasn't room to throw, trying to plunge it into the Joker's leg. It would've been closer and easier for him to reach the vital organs in the Joker's abdomen, but that wasn't Batman's way.