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
Ben has changed his disguise and now wears a doctor’s clothes. He knows he doesn’t have much time and wonders if he should have killed Kistner, although he ultimately decides it would’ve been wrong because Kistner doesn’t seem to be one of the aliens. Ben hears an air raid siren going off and is glad of the distraction. As he makes through the hospital corridor on his way toward Nugget, all of a sudden, he comes across an object that looks like a large eye. It starts flashing lights at him.
Whereas Dr. Pam used the authority of a doctor’s position to convince people to kill former allies by pressing an execution button, Ben learns to use the authority that comes with a doctor’s outfit to pass through the halls without being questioned. Ben’s decision not to kill Kistner, who is a witness to Ben’s escape, shows how even in desperate circumstances, Ben keeps a sense of compassion toward his enemies, to the extent he can.