*** SPOILER ALERT ***
Tan, who is seething with rage, breaks down the door to the room. (That door knob popped out from its place!) Young Do is taken aback and has very little time to react to Tan's punch. Tan's anger is at full momentum. He grabs a chair, ready to thwack Young Do with it, but Eun Sang stops him, hugging him back. He drops the chair and pushes Eun sang out of the room while he and Young Do confront each other. This scene may be a moment of breakthrough for Young Do (it's hard to tell since there are no subs!). He simply lacks his usual smug spirit during this scene and in the ones following after that. On this episode, we learn more about the day Young Do's mom left ... Tan was the last person to see her. Maybe she left a message with him?