To what extent?

In surviving the extremes many outrageous events have occurred this far in the book. For example in the Jungle Chapter the young boy hurts his hand and mud is used to help the hand and soak the blood. In addition in the dessert chapter a young man is forced to drink the blood of a bad as well as drink his own urine when he is desperate. Also, in the outer space chapter another young man is left in the snow to die while speaking with his pregnant wife. These events in the chapters all come to show the extremes of human endurance and what humans can do to survive and how there minds begin to panic at the thought of death,.
The main theme of this chapter is to show how us humans have various body systems that are affected in different forms of nature and how far we can take it before our body goes into panic mode. In addition within these first few chapters we learn how a doctor can substitute equipment in these extreme environments to ensure patient health.
These chapters in the book also come to show what extent humans can go to gain knowledge on place that humans are not yet aware. In addition, doctors such as the author writing the book may go trips like this to gain experience. At the end of the day this comes to show what extents we can go to gain knowledge, experience, and where our curiosity can drive us.