Grey’s Anatomy has featured a number of notable guest stars over the course of its 19 seasons (some that we’re sure you’ve forgotten about), and that includes Mandy Moore in a four-episode arc. Years before portraying matriarch Rebecca Pearson on This Is Us, Moore appeared in the final episodes of Season 6 — in which an active shooter injured and killed a number of the Seattle doctors. Moore talked about her experience on Grey’s Anatomy, recalling how everybody was “walking on eggshells” amidst the serious subject matter.
The two-part Season 6 finale, “Sanctuary” and “Death and All His Friends,” are two of Grey’s Anatomy’s best episodes, and Mandy Moore didn’t just witness that moment in TV history — she was a part of it. Moore played Mary Portman, who was a patient under Miranda Bailey’s (Chandra Wilson) care at the time of the shooting, and Moore told AV Club what it was like to be offered a role for that iconic storyline:
