No. Donghyun was there when sooyoung got stabbed. He saw taesung with calm face taking sooyoung at the end (its part manipulative plan of taesung that donghyun eleborate it) and so he got to know that sooyoung is someone important to the mafia boss park taesung. Donghyun remember everything on that day. If he could tell the detail, sooyoung might know the truth that taesung didn't come to saves him earlier because he want to manipulate him to rely on him, to make him trauma of looking trouble.
now is another incident. Remember minhyuk fucked an old man? Its the senator. Minhyuk recorded their sex and blackmailed him. Donghyun know that the senator knew taesung since the mayor has the deal with taesung but the senator didn't believe him. He thought sooyoung was another prostitute that serve taesung.
Ohh so it is another part when the two of them tried to search something is it? When there is a head burried in the tank thats what you are talking about?
So are these previous chapters are the more elaborated stories of what we have read before? Bcs as far as I remember i already read the part when minhyuk removed the knife that was stabbed on sooyoung? And then there is also taesung?? Or its a different scene? Or it is? Im confusionism rn. Thanks