The post-apocalypse
This novel includes post-apocalyptic imagery, like an apparently invincible government with absolute control over the lives of the people who still live. For the characters in this book, there is nothing to do, nothing worth fighting for, except to try to restore some semblance of peace and democracy to their society, but they are way past the tipping point. For Cia, the story is one long trail of revelations that are horrifying to her, where she peaks behind the veil to see the grim reality of their situation.
Absolute tyranny
The government anticipates any attempts to thwart its plans. For instance, it tests the society and removes undesirables through a process called "redirection" which is just murder. They just murder anyone they don't like. When the people try to organize, those attempts are also thwarted, because the government literally invented the resistance movement to catch people who would dare to organize against them. The imagery suggested is absolute tyranny and domination by a corrupt government.
Paranoia
To Cia and friends, the reality of their lives are riddle with paranoia, because they know that it is like that the government is probably up to something. They don't know how much the government knows, and they try to resist the government by making a rebellion, but that process is full of fear, because they don't actually expect to win, and because what they're doing is the most dangerous thing they could possible do.
Death and horror
To Cia, the imagery of death comes with absolute horror. She encounters the death of Obadiah accidental, so that she is randomly confronted with the death of a friend at the hands of government employees. She realizes that "redirection" is just murder, and suddenly, she realizes that she is in dire straights. The government doesn't just execute criminals—they execute anyone they don't want in the society. She realizes her own life is at stake, which is horrifying, and the novel explains how she responds to that realization.
