Contains spoilers for this episode and earlier episodes.
The confrontation in the lobby becomes a gunfight when two men among the security officers reveal themselves as Soo-ho's comrades. Gang-mu is shot while protecting Han-na, and the remaining officers struggle to contain the three spies. Soo-ho straps grenades to himself and uses Yeong-ro to force them back. The students and staff are gathered in the cafeteria, with exits trapped and weapons trained on them. Yeong-ro asks to treat Gang-mu's bleeding shoulder and brings medical supplies despite the danger. She also slips him a metal implement that could help loosen his bonds. Soo-ho's threats leave her confronting the difference between the wounded man she sheltered and the armed captor now controlling the dormitory.
Outside, Eun Chang-su and Nam Tae-il argue over a crisis that endangers their arrangement with the North. Chang-su learns that his daughter Yeong-ro is inside. He contacts Soo-ho and demonstrates knowledge of the operation, offering a route out through the secret passage. A coded radio instruction tells the spies to cooperate with the South, although Soo-ho's comrades doubt the promise. At sea, Professor Han tries to attract a coast guard patrol's attention and is shot. Gunfire follows, and the boat carrying the professor and Northern operatives is sunk. Yeong-ro's brother Yeong-u is serving aboard the patrol. The changed situation prompts another order outside the dormitory: when Soo-ho and his men attempt the promised exit, lights, gas and gunfire greet them.