
The doctor said that it seems like Yoonwoo( MC) has been "exposed" to Milk drug for a very long time, to the point of developing resistance against its side effects. So who has been drugging him?? It can only be the Silver haired dude. Also, would explain why he wanted to by "half it back" from Alejandro... maybe.
https://www.mangago.zone/read-manga/prison_breakfast/uu/br_chapter-246858/pg-20/