Yunjin's interview with spoilers for finale season5

Favorite episode?

"I think it would have to be from season one. It's the episode where you see Locke and you see him sitting, and slowly the camera pulls back, and you see that he's in a wheelchair. It's so surprising. Even though I knew it was coming, when I saw the episode and how beautifully it was done, I was so impressed."

What you like most about your character?

"I'm grateful she has so many layers and that's she's developed so much. I mean, to go from being the kind of woman who had to button up her sweaters to meet her husband's approval to being the woman who plots revenge is incredible. For Sun to be able to pretend to forgive Kate, lie to her and deceive her like that means she has come a long way from where she started."

What was the most shocking twist in the storyline?

"There's a huge twist in the season finale. It's the best one to me, and I can't talk about it. When I read it, I couldn't stop thinking about it. It's part of that secret scene. I think it tops everything that's happened before this point. I would love to talk about it, but I can't."

source : variety.com yunjin kim interview