"Because you are me and I am you."

In "Kill Me Heal Me" Cha Do Hyun (played by Ji Sung) looked into the mirror. In the mirror, he saw himself and at the same time, saw Shin Se Ki (played by Ji Sung).

On this episode, Do Hyun heard from Oh Ri Jin (played by Hwang Jung Eum) that he himself had been abused as a child. He was shocked and asked Ri Jin, "Why didn't you say anything to me all this time?" Ri Jin replied, "Well if you find out that you were abused, then you might get hurt."

Nonetheless, Do Hyun vowed that he would not back down like before. He looked into the mirror as he cleared up the steam. Then, from out of nowhere was his second personality from Se Ki as his voice rang out. Cha Do Hyun suddenly then transformed into the looks of Shin Se Ki.

In the mirror, Se Ki said, "How about you clean up your past?" and stared at Do Hyun with a sharp glare. Do Hyun stared back and said, "Ditto. From now on, I'm going to think about all the memories that I had lost and I'm going to find out everything about the truth." He showed that he would not back down at all.

At this, Se Ki said, "Do you want me to? Or will you? And he said, "Of course I will. I'm not going to avoid things from now on."