How Sang-woo’s fate was foreshadowed
In episode 2, Sang-woo is confronted with the reality of his mounting debt that he cannot pay, and he resolves to take his own life. He stops himself from doing so when a persistent knock on the door appeals to him not to end his life.
During the tournament’s last bout, he’s given a chance for forgiveness. Still, he turns down the opportunity to return to reality with no money and follows through on his initial plan of committing suicide.