In Fahrenheit 451, what does Montag learn about the excessive cruelty of young people as he is making his escape?
In Part 3, Montag becomes a fugitive after killing Captain Beatty but suffers a severe leg injury when the Mechanical Hound stabs him with its procaine needle. While Montag is staggering through the city, attempting to hide from the authorities, he realizes that he must cross a ten-lane highway in order to escape.
As Montag is making his way across the boulevard, a Beetle full of teenagers attempts to run him over but narrowly swerves at the last second after seeing Montag fall on his face. Fortunately, Montag makes it across the highway safely before he contemplates the brutality of the teenagers.
Montag is shocked and disturbed after analyzing the cruelty and extensive brutality of teenagers in his society. He realizes that the teenagers' idea of fun is to race through the city at high speeds and run over innocent pedestrians. The only reason they had purposely avoided Montag at the last second was to avoid flipping their car. Montag then shivers as he wonders whether or not those same teenagers were responsible for Clarisse's death. In Bradbury's dystopian society, teenagers are callous, brutal individuals, who are willing to kill people, considering it to be fun.
In Part Three of Fahrenheit 451, as Montag makes his escape across the highway, he learns an important lesson about the cruelty of young people. This occurs after a group of joyriding teenagers, driving at "five or six hundred miles" per hour, almost hit him with their car. Montag then realises how cruel young people can be: "For no reason at all in the world, they would have killed me."
In other words, Montag realises that young people in his society place a higher value on enjoying themselves (by driving fast along the highway) than on the lives of their fellow citizens. In their minds, Montag, as he walks across the highway, is nothing more than an obstacle on the road ahead and killing him is an act of little significance. Fortunately, however, Montag's life is saved, but only by sheer chance.
It is the callousness of these teenagers which makes Montag wonder if Clarisse was killed in a hit-and-run accident. This possibility infuriates Montag and makes Montag even more determined to escape the city and build a new life.
We learn about the cruelty of the young early on. Clarisse comments on how many teenagers die in car accidents, get into vicious fights, and kill themselves by overdosing. Toward the end, as Montag flees, the cruelty of society is illuminated. Because the authorities cannot catch him, they sacrifice an innocent man by posing him as Montag and setting the hound on him. He is attacked and dies on live television.