They might immediately stop the concert. The members would be really worried. For example, Jin could rush over to where Y N is with a concerned look on his face. He might ask the medical staff what's wrong and offer words of comfort.
Honestly, 'y f n' in fanfic could be a random combination of letters without a widely recognized meaning. Maybe it's a made-up term by the author for a special plot element or character trait.
Y n was all set for their flight. Little did they know that this flight would be the most memorable one. As they boarded the plane, there they were - BTS. Y n's heart started pounding. After getting over the initial shock, y n managed to strike up a conversation. They talked about music, travels, and the beauty of different cultures. The whole flight passed by in a blur of laughter and interesting discussions for y n and BTS.
Well, perhaps y n is traveling for a very important reason, like a job interview or a family event. They see BTS on the plane. BTS notices y n's unique style or something interesting about them. They start talking, and BTS finds out about y n's situation. They give y n some really inspiring advice that changes y n's perspective on their upcoming event. And in return, y n shares some interesting local knowledge about the destination with BTS.
One day, Y N was on a plane, feeling both excited and a bit nervous for the journey ahead. As Y N was settling into the seat, suddenly, the members of BTS gang walked by. Their presence was electrifying. Y N couldn't believe their eyes. Jin flashed his warm smile, while J - Hope's positive energy seemed to fill the whole aisle. Jungkook was looking cool as always. Y N shyly said hello, and they were kind enough to start a conversation. It was like a dream come true for Y N on that plane ride.
One common theme is probably the healing process. Since there's the 'hurt y n' part, often the BTS members will be involved in helping the character heal from whatever has hurt them.
I'm not entirely sure specifically what that particular 'bts y n is a hybrid hurt fanfiction' is about without more context. It could be a fan - created story that involves the BTS members, some kind of 'y n' (which might be a made - up or specific character in the fanfic world), and it's a 'hybrid' concept which could mean a mix of different elements like human and something else, perhaps supernatural, and 'hurt' might imply there are elements of pain or emotional distress in the story.