In The Hollywood Reporter excerpt of "How to Save a Life: The Inside Story of Grey's Anatomy," it's established that Dempsey was a "charismatic" figure both on and off set. He defended Brooke Smith when her character, Dr. Erica Hahn, was written off the show. But then, something changed, with Parriott saying, "He had this hold on the set where he knew he could stop production and scare people. The network and studio came down and we had sessions with them. I think he was just done with the show. He didn't like the inconvenience of coming in every day and working. He and Shonda [Rhimes] were at each other's throats."
The eighth chapter of the book that was shared with THR also features the perspectives of Ellen Pompeo, who notes Dempsey didn't seem to realize how hard the cast and crew around him were working, and the actor himself, who said, "It's ten months, fifteen hours a day. You never know your schedule." Given the star's complaints, in the book, a producer named Jeannine Renshaw claims Rhimes gave the network an ultimatum that either she would go or Dempsey had to.
Of course, we all know what happened. Whether or not the story behind the actor's exit is true, we may never know for sure.
