Much of the film was rewritten throughout production and typically on the day each scene was supposed to shoot. According to Davis, he never met with credited screenwriter David Twohy, whose main contribution was writing the train crash. Beyond that, Davis said "he wasn’t involved in anything we did. Jeb Stuart was there with us...basically responding to things we were coming up with all the time...Bros. can’t talk about this because of the Writers Guild, but Tommy Lee Jones, myself, Harrison and other people who were close with us, especially coming up with the whole plot about the pharmaceuticals, they were uncredited writers." Jane Lynch, who was cast as Dr. Kathy Wahlund in one of her first film roles, recalled having that experience, with both Ford and herself working out new dialogue for their scene right before they filmed it as Ford "didn't like the scene as it was written."