The irony of Obadiah's death
When Obadiah fails his tests, they know he will be redirected, but they don't know that redirection is just another word for government sanctioned execution. When Cia accidentally sees them rolling Obadiah's body away, the truth is revealed to her. This is dramatic irony, because the reader and Cia learn together that the government is up to no good. In fact, they are horrifyingly evil, and Cia doesn't know because they wiped her memory of the Testing.
The memory wipe
The memory wipe itself constitutes dramatic irony because the reader might be familiar with Cia's testing from the last book in the series, but Cia herself is unaware because the government wiped her memory clean. So, she is put in a compromising situation that the reader understands but she does not. This is also dramatic irony, and it points the reader toward the absolute dominion of this tyrannical government, because they control the narrative that she believes.
The irony of Michael Gallen
Michael "saves" Cia from a foolish attempt to escape. He tells her how she can put her life to good use by sacrificing herself for the resistance movement, helping them to gather intel and to help overthrow the government by organizing. When Michael is killed later in the book, the irony is revealed. The "resistance movement" was started by the government in an attempt to find people like Michael and Cia and eliminate them. The irony is that Michael didn't "save" her; he condemned her.
The ironic coup
The government is revealed in the climax of the novel to be supremely powerful, because they anticipated that the people would attempt to form a resistance movement, so they created one themselves so that disenfranchised members of society could join it, which made them easy targets for elimination. The irony is that Cia wasn't fighting the government, she was walking right into a trap.
Education and irony
The education system is presented in a dark way. Instead of representing hope for a better future and education, participation in government sanctioned education systems brings propagandizing and brainwashing, and the risk of going to college is severe. Like the resistance movement, the government has invisible strings in those institutions to help them further their agenda by influencing the younger generation. College is not free or safe.
