Like Brian's ordeal in Hatchet, the significant quotes in the narrative relate to survival. One such quote is seen when Derek is struggling with sleeping at night, while Brian has reverted to his prior survival mode: "You must settle. In your mind. There are some fights you can’t win, and I think this must be one of them." This understanding of the challenge in seeking to survive in nature is reflective of the survival theme that is essential to the story.
Another such quote that underscores the challenge of survival in a condition that does not permit for it would be the simple statement in chapter 4 in which we recognize the challenge in front of Brian mentally and physically: "He remembered the rough parts." It is not a very indepth quote, but it clearly states the condition that Brian must endure with his entry into the wilderness. The mental and physical battle that he must fight through helps to emphasize a critical idea in the story.