The 'Grey's Anatomy' elevator scene with Addison and Meredith was so emotional, even the writer cried seeing it come to life

• Kate Walsh returned to "Grey's Anatomy" on Thursday night.
• In an emotional elevator scene, her character Addison Montgomery expresses a range of emotions.

Kate Walsh returned to "Grey's Anatomy" as Dr. Addison Forbes Montgomery on Thursday night in an episode titled "Hotter than Hell."

While the world-class OBGYN and Maternal Fetal Medicine specialist's presence in the halls of Grey-Sloan might have intimidated residents, fans of the medical drama were reminded that while at the famed Seattle hospital, no one escapes an epic elevator meltdown at some point.

Addison's emotional elevator moment comes after she finishes a uterine transplant surgery on one of her clinical trial patients. After laughing with Meredith (Ellen Pompeo) at residents who had been frantically whispering gossip about the women all day, Dr. Montgomery suddenly breaks down crying to because she doesn't feel Derek Shepherd's presence in the hospital that he loved as much as she expected to.

In an interview after the episode's airing, writer Jamie Denbo told Insider that even though she wrote the words of the scene and knew what was coming, watching the moment come to life was emotional for her. "Even I cried when I saw it and I knew what the scene was," she said, "Watching it come to life was really, really really spectacular for me."

Denbo told Insider she personally believes that Addison came back to Seattle because she thought that so long after her ex-husband Derek's death, "the chapter is closed," and she would feel his presence in a positive way at Grey-Sloan because "he died in the city he loved with the people he loved."

But Addison breaks down in the elevator because she never felt that positive kind of closure. "I think she came back and instead she felt the absence and not the presence," Denbo said.

The writer credits "Grey's Anatomy" showrunner Krista Vernoff with helping to craft the scene because Denbo said Vernoff "wanted to make sure that Kate ran the whole range of emotions" that would come with returning to Seattle for the first time after Derek's death. "We knew that Kate and Ellen could really tackle that kind of emotional rollercoaster," she added.

Denbo was on set when the scene was filmed and said that the episode's director Chandra Wilson was "the perfect director for this" because she is "nurturing" and helped Walsh and Pompeo feel all of the necessary emotions "in the moment."

She added that on a long-running show like "Grey's Anatomy" with such a big cast,"there's something great about doing a little mini one-act play in an elevator," because the chance to explore raw emotions like that can be rare.

Denbo couldn't divulge any details about Addison's potential future in Seattle, but as for why the surgeon waited for so long to come back, the writer mused, "When Addison heard about Derek, she probably went to the beach by herself, cried, and looked at the ocean" remembering her time with him instead of going to a funeral and "causing more pain."

"Grey's Anatomy" airs Thursday nights at 8 p.m. ET on ABC.