In "Scholar Walking in the Night" Lee Joon Ki gave up the life of Lee Yoo Bi's life.

On the 9th episode of MBC Wednesday/Thursday drama "Scholar Walking in the Night" (script Jang Hyun Joo, director Lee Sung Joon) broadcast on August 5th, Jo Yang Sun (played by Lee Yoo Bi) wanted to engage in a commercial transaction with Jo Saeng (played by Jung Kyu Su). In exchange, he was wiling to use Jo Yang Sun's life.

On this day, Kim Sung Yeol had a lot of say. He knew that the weak spot of Yang Sun would be to use his father's life. With that, Kim Sang Yeol said, "If Jo Saeng saw me at Suh Jung Do's house about ten years ago, he would've thought that Suh Jung Do and Nana were all just vampires in the eyes of Nana. They would not be able to separate the secret log."

Soo Hyang (played by Jang Hee Jin) said, "Will you be able to watch Yang Sun get hurt?" Kim Sung Yeol said, "Well I'm also having a tough time and I'm hurt. But if Yang Sun is the only one that's going to die, then I'll do this. If that's the way to get Kwi away, I'll do something even more severe."