Don't Fly High on Final Exams

One sentence summary: In the last semester of the third year of high school, my deskmate said that she was actually the number one swordsman in the immortal world who failed to survive a catastrophe and fell into the mortal world. The protagonist dubiously followed her to practice immortality, but it turned out that there was no normal person among the teachers and students in the school. Core conflict: The day of the final exam coincides with the day when the protagonist transcends the tribulation and ascends to heaven. How can he answer questions in the examination room while fighting against the tribulation, and also deal with the forces of the fairy world who come to "receive" him?