Responses
I don’t think incheol caused her fall/death. That’s just the congresswoman’s way of manipulation to blackmail him into continue following her orders so that he can feel trapped.
and they did reveal what’s important in the file… it’s that pyeonghwa is the son of the mom killed in the past. And he probably knew deep inside but tried not to think about it
So it was actually incheol at last chapter's visit to that woman. And he caused her fall/death... but the author has yet to tell us what is on that file that is so important. Also what is this truth he tried so hard not to see? I think he already knew his boss was shady (and he himself is no flower).