He doesn't give any indication of having heard her, merely corks the last of his phials closed and stows it in his utility belt before he straightens with purpose. "Then what's your excuse?" he asks mildly. He may not know exactly where she is, but fighting in the dark - metaphorically speaking - has never bothered him. He drops a batarang down into his hand, the point of one tip resting against his middle finger, and waits for her to make a move.