Who is Professor Se-jeong and how does she survive?

---

Who is Professor Se-jeong

1. Kwon Se-jeong is a biotechnology professor who lost her university appointment because she wouldn’t tolerate injustice.
2. She attends a biotech conference at a skyscraper (the Doonguri Building), at her ex-husband’s suggestion, partly as a way to try to get a new position—but the outbreak strands her there.
3. She becomes a leader among survivors inside the building, using her expertise to analyze the virus, decipher the infected’s evolving behavior, and guide others toward safety.

---

How Se-jeong Survives (Ending Explained)

Here’s a breakdown of how Se-jeong makes it through the chaos—and what uncertain threads remain.

1. Adapting strategies using her biotech knowledge

   • Se-jeong and the group learn that the infected respond to human body odors, sight, and movement—they even mimic human behavior and voice commands.
   • She uses clever distractions: covering mannequins in perfume, using a mycelium-slime-coated coat to blend in temporarily. Her science-based tactics help them survive dangerous encounters.

2. Final confrontation and disruption of the hive mind

   • On the rooftop and street, Se-jeong triggers the sprinklers to mix water with the pathogen’s fungal elements, causing “system errors” in the infected’s network and temporarily paralyzing them.
   • She also orchestrates an “ant mill” trap: using the mycelium coat on a dummy infected, she causes the infected horde to herd themselves into a vortex-like loop, which overloads their collective behavior and disrupts the hive mind.

3. Se-jeong & Seol-hee survive, but with ambiguity

   • In the end, Se-jeong escapes the building alongside Seol-hee, her external biotechnologist colleague.
   • Seo Young-cheol (the creator of the virus) dies in the climax, caught in the collapsing hive vortex.
   • However, there's a final twist: even after the infected freeze (following Young-cheol’s death), a single infected twitches in the final shot. This suggests the hive’s collapse isn’t total, and the threat isn’t entirely gone.

---

Key Takeaways

• Se-jeong survives largely because of her scientific smarts—reading the infected’s behavior, leading survivors in making distraction/decoy tactics, and using chemistry (mycelium, water) to short-circuit the hive mind.
• The ending is bittersweet—she wins a tactical victory (escaping & surviving), but the larger existential threat of the virus remains open-ended.
• The film leans into themes of individuality vs. collective consciousness, using Se-jeong’s character to argue that identity still matters, especially in the face of forces that demand conformity.

---

If you want a deeper dive into particular scenes—how the “ant mill” works, the role of secondary survivors, or theories about Se-jeong possibly being infected—just say the word.