How does Jack change over the course of the novel, Youngblood?

Jack is intelligent and well-read, frequently making reference to T.E. Lawrence, Tennyson, Yeats, and Caesar. He is also idealistic in the beginning of the novel, believing in the good of the mission in Iraq and that following protocol is the most efficient way to operate. However, as the novel progresses, Jack acquires many of the traits that Chambers possesses, such a disregard to regulations and a focus on survival over the mission.