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
Flintstone doesn’t want to believe that Reznik was sniping at them and that Camp Haven might be run by aliens. Ben shows him the silver device that they found on Reznik. Not trusting what Ben says about the buttons, Flintstone steals the device and presses the button with his number. His head snaps back and he dies. The rest of the squad all get their implants taken out. As they discuss what to do next, Ben says he has to keep his promise to go back for Nugget. Ringer thinks he’s insane.
Flintstone’s flaw as a character is that he can’t accept hard truths, like the fact that sometimes people die in war or that sometimes people in positions of authority can’t be trusted. Flintstone’s stubbornness ends up being his undoing as he kills himself directly because he refuses to listen to Ben. Flintstone’s death raises the stakes and shows the other squad members proof of why they can’t trust their masters at Camp Haven anymore.