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
Back in the hospital, Ben runs away from the eye object he sees. Soon after, the top floors of the hospital explode. There are more explosions, and Ben figures that maybe Vosch is intentionally destroying the base. Ben gets knocked down by one of the blasts and realizes he’s hurt. He thinks of Sissy again.
The explosions in the hospital emphasize how while Vosch and his fellow aliens claim to be colonizing a new planet, what they ultimately bring is destruction. The explosions are a setback that temporarily hold Ben up, but his memories of Sissy motivate him to continue.