Etienne and Marie-Laure continue undermining the Germans by sending secret messages via the radio. Etienne keeps watch over the exterior of his house, since he’s paranoid that soldiers or spies are watching him at all times. He sees a group of people walking out of Claude Levitte’s house, and wonders if Claude is watching him.
Etienne’ eccentricities give him something of an advantage during the war—where an ordinary person would trust that he’s not under surveillance, Etienne, who’s paranoid and uncomfortable with being out in the open even under normal circumstances, suspects Claude (correctly) of spying on him and being an informant for the Germans.
Etienne takes pleasure in his radio broadcasts. He even plays music after finishing a broadcast—Debussy, Ravel, Massenet, etc. Every night, Etienne ends his broadcast, wishes Marie-Laure goodnight, and then goes to his room to pray. He prays that the “horseman of death” will avoid hurting him or Marie-Laure.
It now seems clear what will eventually happen—Werner is going to listen to the radio broadcast, hear the music, and remember his childhood. It’s also worth noting that the French Resistance is bringing Etienne and Marie-Laure closer together—they’re inspiring one another to be brave and act according to their morals.