Lucy is the most compassionate person on the
Dawn Treader, willing to have empathy even for a fearsome dragon. Her willingness to help, even at her own risk, is a form of bravery that shows how much she has grown up over her previous trips to Narnia. Although this passage doesn’t reveal the dragon’s identity, the gold armband strongly implies that it’s Eustace and that Eustace’s impulsive decision to take the armband is what turned him into a dragon in the first place.