The novel is actually a bit clearer on this. So, Dowon and Kwonwoo are both going through their own worst nightmares while in a comatose state and those nightmares are loosely connected. Dowons worst nightmare is Kwonwoo forgetting him again and Kwonwoos worst nightmare is Dowon leaving him. So, none of the situations they had just lived through were real. What's real is Kwonwoo waking up and seeing Dowon in a coma in the hospital and being pissed at the doctors and Dowon asking Kwonwoo if he still remembers him. There's no real amnesia arc except for the very very beginning of the story. I hope that clears anything up, if not ask me and I'll try to elaborate where I can.

I'm so confused, so ml didn't forget mc the second time? It was all in his inner world? When mc decided to take that drug with side effects to better guide ml so he could wake up, MC ended up bedridden himself after? Like he didn't wake up the next day only to see ml losing his memories of him for the second time, that scene was all made up from Ml's inner world? The reality is that after mc increased his guiding output through that drug, he ended up bedridden, then ml woke up, trying to find mc and we have this chapter? Sorry for the question marks but I need clarifications ToT