The dragon is clearly growing desperate, as the fight drags on, but with a broken wing, it's only chance of escape is to kill Caiphias. Almost frantically, it throws itself at him, scrabbling at his shield, snapping and clawing and thrashing, trying to get in, under his shield, or past it, to rip at his flesh and tear him apart. A few more arrows land, but most bounce off his scaly back, or pierce a wing, and only see to enrage him further.