S11, E9: On Christmas Eve, the emergency room staff scrambles to finish work and go home for the holiday. While Abby treats a dialysis patient who is in critical condition, she can't reach his personal physician because he doesn't want to be disturbed during the holidays. Meanwhile, after much effort, a distraught Chen finally finds someone to work her shift so she can take care of her ailing father. Concerned for her, Pratt stops by her house and finds her struggling with her father's worsening health. Carter and Wendall (recurring guest star Mädchen Amick) grow closer and share an awkward kiss as they wish each other a merry Christmas.