Theme Is the Secret Writer's Tool

The pattern set up from the initial two episodes creates pressure for the audience. Part of what makes this surprising beauty of Bill and Frank's little apocalyptic romance feel so fragile is the expectation that zombies are coming at any moment. The episode works without even a single zombie. Theme is the glue that ties The Last of Us together through all its tonal variations and surprises just like it's going to be the glue that tie your show together.