Hae anseon (2002)

At South Korea's border with the North, troops guard the coast. Each bullies those ranking beneath him; tensions are high. PFC Kang and his friend Private Kim are on patrol when drinking youths jeer them. Two nights later, Kang follows orders, opening fire at a person who has infiltrated the border zone. It proves to be a young man, one from the earlier encounter, on a drunken tryst with his girlfriend, Mi-yeong. Kang is commended, yet horrified. Mi-yeong is unhinged. Kim tries to hold onto friendship, duty, and his humanity. While Kang retreats into bizarre behavior and violence, Mi-yeong becomes easy prey to soldiers. Sickness is all.