The ironic use of gangs
Mexican criminal operations are so well-established that if one wants to flee the terrorism and tyranny of the Mexican cartels, one must employ other illegal operations to help with emigration. The operation in this famous instance is "The Cercas Family," a conglomeration of gangs and coyotes who collect funds and hire guides to assist the men with passage. The gang is the underworld version of a travel agency. The men must break the law to escape the lawless cartels of Mexico.
Drama and the cartel
There is dramatic irony about the Mexican cartels that Urrea helps to explicate. For instance, many people are under the impression that Mexicans illegally immigrate into the United States just for money, because wages are better on this side of the border, but that is not the case. Because of the dramatic irony caused by American privilege, the true horror and danger of Mexican cartels must be taught and explained. The cartels are extreme and barbaric, and they are so powerful that the police and the government are not able to contain them. It is the corruption of the Mexican state that makes life there so painful and scary that people try to escape. The irony points to the immigrants as refugees.
The risk of life and death
If illegal immigrants are just trying to get better jobs and more money (which is just a projection of the American Dream where it does not actually apply), then why would they risk their lives, literally? The risk they are willing to undertake is situationally ironic because they know when they depart that chances are pretty good that they will all die. In fact, the survival of any of them is a miracle in itself, because as the book details, death is around every corner in the Arizonian desert. They willingly undertake that risk. They irony should make the reader ask "Why?" The answer is because Mexico life is often that dangerous for its citizens anyway.
The desert threats
When a person thinks about the US-Mexican desert, the imagery that comes to mind is probably the heat and the sun. Ironically, some of the main threats of the desert are actually freezing temperatures through the night. Many people experience hypothermia. During the day, it is often uncomfortably hot, but then, at night, the temperature drops. The dramatic irony of the desert is also looming in other ways. There are scorpions, wolves, coyotes, spiders, snakes, and of course, there is the risk of starvation.
The absolute irony of jail
Imagine nearly dying as a refugee to find some new way to survive, and then going to jail. Their crime is that they illegally crossed into the United States, and their punishment is jail time before being deported. Ironically, that means that their time in jail is technically the safest time they have in the entire book. Their homes are disintegrating due to government corruption and the rise of the cartels; their passage through the desert leaves many of them literally dead; and when they get deported back, they will be treated hostilely by those who await them on the other side of the border. Even jail of all places is safest.
