We are TALKING about this ending. I can not believe that he killed of more than half of the class and we didn't get any resolve. I wanted to see Chi Yeol and Na Ra's situation because they both happened to live, but we didn't get anything on her or the other survivors...MY HEART IS EMPTY!! I'm feel so sad without this show cause I really enjoyed the plot and actors. If only the ending, and certain missing plot points like Won Bin disappearing, or the DEAD MAIN LEADS DYING QUICK, were different, my view would be raised for this series! Overall, the casting was perfect, and the production was really smooth and nice to watch. I'm gonna miss this so much 😢