This is a situation that a bad guy, Taemu fell into his own trap... He tried to reveal his cousin, TaeYong who is supposed to become a president of the company has lapsed into unconsciousness in front of all board members... It's because Taemu wanted to get the position of president! so he killed Taeyong before, but Taeyong was alive. While revealing Taeyong's status, suddenly TaeYong lying on the bed got up and talked to him. So it's time to unfold Taemu's sins instead.
There's a Korean saying that describe this kinda situation : 제 꾀에 제가 넘어가다.
It means "you fell a victim to your schemes." or "you fell into your own trap."
What's English words for this?
** for original stories of the drama : http://www.vingle.net/rooftop-prince