LitCharts assigns a color and icon to each theme in The 5th Wave, which you can use to track the themes throughout the work.
Trust and Belief
Survival and Perseverance
Warfare and Dehumanization
Family
Summary
Analysis
Sammy notices that Ben is bleeding, but Ben says it’s a story for later. He remembers that they have to take out Sammy’s tracker. Cassie reassures Sammy that this is true and that his commanders have lied to him. They get Sammy’s tracker out, but just as they go down a new corridor, a familiar voice calls Ben by name: Vosch.
While removing the microchip tracker is a physical process, it also symbolizes the mental process of removing Sammy’s delusions about his commanders. Sammy’s good nature, which helped him unite Ben and Cassie, also made him vulnerable to the alien propaganda, but this passage shows how when people work together, the truth can finally come out.