be flawed, she gets to be tired, she can be cranky, she can be grumpy." Showrunner Shonda Rhimes explained that the idea of Miranda Bailey having a child was developed after Chandra Wilson had already been pregnant for 6 months. Cast member Kate Walsh deemed Wilson's portrayal of her character "sweet and wonderful", naming her a professional: "She makes you be a better actor, just by being there." She also described her performance during her character's labor as "heart-breaking, tender, powerful and wonderful", noting how she managed to transform the strong character into "a weak woman, struggling to fight the unusual situation." Fellow cast member James Pickens, Jr. described Wilson's portrayal of Miranda Bailey as "a breath of fresh air, literally and figuratively", also noting how the force she delivers is mainly due to the start of her career being in theater. Horton also described the production process of the 2-part story arc, which he stated to have been planning since the beginning of the series. He stated that the plot of the episodes had to "fill the demands of the Super Bowl", which was scheduled to air in the same night: "We really wanted something different and Shonda [Rhimes] came up with the idea of this bomb, that we found simply outstanding!" Visual effects supervisor Scott Milnex noted how "breaking down the story boards was really the key to getting all the departments to work together." He also assessed that the necessity to use Primacord, an element they had been trying to avoid, for the explosion scene proved excessively dangerous, and was ultimately replaced with wood and clothing material. He described the filming process by emphasizing the transition from mannequin to the real actor: "When we filmed it, there was a moment, a fraction of a second, when we changed the body with the actor." Casting The second season had 10 roles receiving star billing, out of whom 9 were returning from the first season. All the actors who appear as series-regulars portray physicians from the fictional Seattle Grace Hospital, specialized in surgery. Ellen Pompeo acted as Meredith Grey, the protagonist and the narrator of the series, a surgical intern who struggles to balance the difficulties of the competitive career she has chosen, with her troubled personal background. Sandra Oh portrayed highly competitive intern Cristina Yang, who suffers a miscarriage just as she starts accepting her upcoming motherhood. Katherine