Among all the plot twists and turns presented in the “Grey’s Anatomy” Season 7 episode 6, the one which received an immediate cry of concern from fans was the news that Arizona (Jessica Capshaw) would be accepting a grant and taking her pediatric surgeon skills to Africa—with Callie (Sara Ramirez) in tow.

 Anyone who has been following Season 7 of “Grey’s Anatomy” is well aware that thus far, Callie and Arizona’s problems have been mostly domestic; what color to paint the walls, apartment décor, and even Callie’s friendship with Mark (Eric Dane). Capshaw recently gave birth to her second child, which might explain Arizona’s absence; even beloved TV stars need rest and time with newborns--but what about Callie? Ramirez recently sat down with TV Guide and discussed this surprise development, which I detailed in this article.

This week’s “Grey’s Anatomy” episode was filmed documentary style, supposedly as a follow-up by a Seattle TV station after the murder-spree shooting from the Season 6 finale. The alternative method of filming was a refreshing change, and it was impressive that the actors managed to remain in-character as doctors who are not actors; most of their on-air dialog during the episode seemed awkward, forced or sincerely natural.

 Episode 6 also marked the return of Mandy Moore, who reprised her role as Mary Portman, the patient introduced in the Season 6 finale. Mary was a source of moral support to Bailey (Chandra Wilson), and the pair survived the ordeal—including the death of Dr. Percy (Robert Baker)—but her surgery went uncompleted. Mary served as one of the mandatory medical cases for this week’s “Grey’s Anatomy” cast; unfortunately, Moore’s characters also served as a reminder of the dangers of even a routine, simple surgery. Bailey was pleased that Mary operation was a success, but viewers discovered a few short scenes later that Mary slipped into a coma, never awaking after the procedure, and her life support was terminated in the closing scenes. As always, Moore’s performance was authentic, endearing, and a great guest star appearance.

 Another medical case challenging the surgeons at Seattle Grace this week was a patient receiving arm transplants. The gentleman had lost both of his limbs in a work accident, and after an unfortunate death of a motorcyclist—who matched him for blood type, gender, and such—Callie, Derek (Patrick Dempsey), Mark and Owen (Kevin McKidd) successfully transplanted both limbs onto his arms. One of the new limbs had the name “Nicole” tattooed on the forearm, which Callie initially had worried would cause the patient and his wife to reject the transplant; to her surprise, the pair exclaimed that they loved the name Nicole, and at the end of the episode viewers learned that the patient tattooed “Thank You” beneath the original ink. The patient’s wife, Nicole, appeared during the show and shared her pain at the loss of her husband, and the story of the day he proposed—the day he got the tattoo.

 Alex (Justin Chambers) continued to slip closer and closer into specialization in pediatric surgery, a development which started with Addison (Kate Walsh) in earlier “Grey’s Anatomy” seasons. Lily, a young girl with a growth on her trachea which was inhibiting breathing, managed to secure the reluctant and often-denied devotion of the rebellious surgeon. When Arizona discovered that the benign growth was inoperable, the staff at Seattle Grace worked together to devise a plan to grow Lily a new trachea. Alex made this a pet-project, sleeping at the hospital—often beside the young patient—until the successful surgery. Afterward, Lily took Alex with her to show-and-tell for her class, as the best part of her hospital experience.

 Trouble with the new security system at Seattle Grace plagued the staff, especially with Lexie (Chyler Leigh) was stopped at the entrance during the arm transplant surgery. She rushed through the metal detectors, setting off the system and locking-down the doors on several floors. Avery (Jesse Williams) was caught between two sets of doors with a patient, who coded; Terry (Kim Raver) managed to provoke one of the security officers into overwriting the system, allowing her to get to Avery and assist with the patient. By the end of "Grey's Anatomy" episode 6, the security system had been dismantled and removed from the premises.

 Cristina (Sandra Oh) continued to inch her way back into the field of medicine, working with Meredith (Ellen Pompeo) in the pit, but declining to go into surgery. She and Meredith sat down with the mock camera crew later in the episode, and Meredith expressed her opinion that Cristina was a hero—at least to her—in light of her bravery after the shooting, and ultimate life-saving surgery on Derek. Cristina cut her off, asking her to stop. Yet, at the end of this week’s “Grey’s Anatomy” episode, Cristina sat-down again, alone this time, in front of the mock camera crew. Her tone was forced, and vaguely insincere, as she explained: “Well, we went through the scariest thing a person can go through, and we survived. So, now every day is a gift, and we’re all just blessed. Blessed to be here; blessed to be doing what we do best, which is saving lives—everyday—one life at a time. We’re healed, so we can continue healing others.” The interviewer asked her if there was any one thing she would take away from the ordeal, to which she soberly replied: “Being a hero has its price.”