Hobie saw the letter that the "owner" of Duke sent to him. He was scared to open it because he never knows what it might say.
Hobie read the letter. It says that Duke got shot. Hobie had no idea what to think. P.F. Corff, Duke's commander, said that his group was attacked and Duke took the bullets for him. It also said that Duke will be okay it will just take a long time to recover.
Hobie did not know how to react, so he got on his bike and went as fast as he could. Duke got shot and his dad is being held as a prisoner of war. Even though, he knows it's all going to be okay he is still very scared. I think that this is important because there would be a lot going on in a young boys life and he has to learn how to deal with it. It is a huge coming of age moment of when a boy becomes a man.