On the air for about fifteen years, Emergency Room saw the deaths and abrupt departures of many beloved characters, most notably Dr. Mark Greene in season 8 – but why did actor Anthony Edwards leave Emergency Room? Created by doctor and science fiction novelist Michael Crichton (creator of Jurassic Park and Western World), Emergency Room premiered on NBC in 1994, achieving overwhelming success with a total of 331 episodes over 15 seasons before ending in 2009, becoming the second longest-running medical drama behind Grey’s Anatomy. As Grey’s AnatomyMany cast members came and went throughout the long-running series, but Dr. Mark…