Responses
Wait I know the translation and flashbacks are confusing but Sena didn’t fake losing his memories. At the start he actually did lose his memories (dissociative amnesia), likely from shock. He says later it might’ve been his mind subconsciously wanting to have a fresh start. After meeting at the hospital, he slowly starts to get his memories back. I think Sena was begging Shu to go back to being normal because it seems before they weren’t officially in a relationship, so after the mom caught them he probably thought the only way they could stay together is if they went back to being friends, something like that
So basically from my view Sena faked losing his memories after Shu got hit by truck/car,
so Shu and him can have a fresh start from where they basically first talked [which I think it’s the high school years by the sea] but Shu again acted the same way as he did when they were together before {as “normal” friends}
(basically Shu likes Sena but he is afraid to show his feelings because He doesn’t want to be different from what’s “normal” in this world) basically Shu wants to say is the people in this “normal” world wont accept him as who he is and will treat him differently as he isn’t “normal”, And Shu doesn’t want to drag Sena with him there. [oh and if so he shows his feelings he says they won’t be able to go back being “normal” friends anymore] ..
the author has rushed the story which is annoying confusing to understand the whole thing going on, like for example the part where it wasn’t really clear what happened after Shu’s mom saw them kissing each other, the way Sena was begging Shu to go back being “normal” friends was quite the scene..