Soojin Park is the film's moral center: a late-twenties senior engineer and Zheng's former graduate student who does not trust Meridian from the start. Four years before the story begins, her twin sister died in a structural failure at a site certified by an early AI model—the same model family that evolved into Meridian. Soojin joined Veritas deliberately, hoping to prevent another disaster. When she discovers the flaw, she becomes the only person in the room willing to say it aloud and act on it, even knowing it will destroy the company. She is serious beyond her years, unafraid of authority, and carries quiet grief that sharpens into clarity. Hers is a role requiring intellectual precision, emotional restraint, and absolute moral conviction under pressure.