Wait, why did he do that expression
If you're talking about Goto, I think he noticed Jin-woo's shadow soldier hiding his shadow, at the end of the chapter.
I think he felt murderous intent when Jin Woo got serious and he realized that he's way stronger than he thought
nope
Because Goto's is really arrogant in his power and he's thinking 'I have just seen a really scary guy.'. He's in shock.
Wait, why did he do that expression