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
Cassie goes back to get the silver device from Dr. Pam, but Dr. Pam has woken up. She presses the button to terminate Cassie, but Cassie has transferred the chip to Dr. Pam herself, and so Dr. Pam dies instantly. Cassie has no Plan C, so she runs into the hall. As she tries to figure out what to do, she runs right into a strange man’s chest. She recognizes his voice: it’s Vosch. He asks if she’s lost.
In attempting to kill Cassie, Dr. Pam kills herself, in a reflection of how violence in general tends to have a self-destructive element to it, even when that’s not the intention. Meanwhile, Cassie is forced to trust her gut and believe that things will work out once she is forced to start implementing her nonexistent Plan C. The sudden appearance of Vosch doesn’t bode well for that plan.