what no actually at the end jungwoo is pointing out that the prof probably lied to him and that he shouldn't believe his words as well. How I got it he was yelling at Youngmin for not telling him about it. Maybe you should go read again uhm..
This is right. He didn't even mention the rape, what they were talking about is how the Prof told him to suck him off or he'd tell Jungwoo everything and how the Prof told him how their drunk night went. Jungwoo was yelling at him because he believes everything the Prof says. That last panel was the MC realizing that he's been saying everything based on what the Prof told him.
Omg do I have to spell it out. He's shocked because they are BOTH realizing that he is a rape victim. Seriously, can you people read in context.
screaming at a rape victim because he didn't realize he got raped... grow the fuck up Jungwoo