Billy Burke left "Fire Country" primarily due to a creative decision made by the show's writers, not because of his personal choice. His departure was part of a storyline development in Season 4, where his character, Vince Leone, was killed off during a catastrophic fire incident at the end of Season 3. The decision to write off his character aimed to stay true to the real dangers faced by firefighters and to create a significant emotional impact that would propel the story forward and allow the remaining characters to grow and face new challenges.