Jisung promised to protect Minho forever. Hw, he used to be in a mysterious organization which claimed that if he betrayed and left them, they would kill all of his beloved ones (’cause they couldn’t kill him). Therefore, Jisung had to fight to protect Minho but in the end, he knew that only when he left Minho, would Minho be safe forever. Finally, he broke his promise to always stay with Minho. Coming back to the organization, he got himself a death sentence and gave Minho a peaceful life in exchange.