A flicker of movement catches his eye; a humanoid figure lurking in the shadows, something small moving away from their position, as they quickly reposition themselves; a grenade, from the looks of it. The clattering sound would certainly have caught his attention, if the movement didn't, but he's able to track his foe's movements, moving to a position to strike a wide area, hoping he'll expose himself, or be flushed out by the grenade, which did not land near him.