The song "Who Killed Bambi?" is constantly used throughout Zero Day, and here's what it means and how it connects to Robert De Niro's character.

By the end of the finale, Mullen seems to have kept the symptoms mostly at bay as he returns to his quiet private life. The final sequence reveals President Mullen burning the pages of his memoir manuscript—his legacy has been irrevocably altered for better or worse—before heading out for a walk with his dog.