Just what is Lee Joon's character up to in 'Iris 2'?

He plays Yoon Shi Hyuk, one of the top agents in NSS on the show. However, lately viewers have noticed that his actions are quite bizarre, and many have even gone forward to suggest that he would ultimately betray NSS. For example, instead of shooting at David McInnis while he ran away, he pointed his gun into empty space and shot it. In another scene, he pointed his gun at Jang Hyuk's character.

One of the 'Iris 2' representatives said, "During this week's episodes, the veil around Yoon Shi Hyuk, who has been helping Choi Min as an independent informant, will be lifted. There will also be an unexpected sacrifice, so please carefully look at his identity that is slowly surfacing."

What do you think his true identity could be?