Shooting The "Roadrat"

The episode of shooting the man in the truck is both shocking and expected as the man has no other choice because it is a matter of survival and he can't afford to value anybody else's lives. The calm conversation shared between them before the shooting about food and where they are going is quickly interrupted by his description of the bullet, saying "the bullet travels faster than sound. It will be in your brain before you can hear it..." is chilling because his detailed description shows his knowledge of guns which hints that he will shoot the man if he really has to. The short, one sentence structure of their sentences ends when the man describes in great detail the shooting of the man, almost showing the reader that the man has a sense of pride in what he has just done by the level of description.
The use of the road rat in the novel provides the reader with doubts over if they actually are the 'good guys' as he was able to kill him just as easily as they are able to to him. The man is surely a 'bad guy' as well for killing another 'bad guy' although he does this to protect his son, showing that although their relationship is seen as distant, he is willing to go to great lengths to ensure he is safe.
This is a key episode in the book because again, they are meeting someone new throughout a novel where is is largely just based on two people. They interact with other humans warily and cautiously, suggesting that they trust nobody anymore because everyone is so desperate to survive their morals have completely disappeared.
When the man is killed, the boy's face is described as having 'no expression at all', this could be because he feels nothing towards people anymore after being so detatched from the world he has previously known or because he feels no remorse for a man who has attempted to kill him himself. The fact that none of this is surprising to him shows that the way in which they behave now has just become a way of life and if you don't protect yourself, somebody else will kill you to save themselves.