This is my favourite shot of Shin Jae Ha in the entirety of season 2.
As an actor myself, I can't stop thinking about it because - LOOK. He is insane for capturing all that on his face in one go. Do you see how it's brimming with conflict and visceral emotions that look only barely contained???
But that's not even the best part.
This scene is the climax of his character arc. And the fact that you already know before he's even said a word that THIS is the most tortured his character has ever felt, the fact that you can tell just by looking at him- at the unspilled tears in his eyes, the tension in his facial muscles, the abject grief in his brow- is flipping monumental. His character never had this look on his face before, not once in the 15 episodes before this. Ever.
And that tells me he lived and breathed as On Ha Jun from start to finish. He was mad for this role and I respect him so fucking much for that.