An Idea That Goes Back Through the Book

(Suddenly I really want to read a story like this. Let me make some assumptions first. I may change the plot when I have time to refine it in the future.) Gong has been working in a big city far away from his hometown for many years. One day, he reunited with his middle school classmate in the laboratory. Before even exchanging a few words, he encountered a laboratory accident. To Gong's surprise, he did not die, but the whole world collapsed, and Gong glimpsed the original appearance of the world through the cracks in the universe. It turns out that Shou is the protagonist of a beautiful and tragic inspirational novel. The stability of the world line is maintained by his existence. Shou must not die in a laboratory accident. The world line bounced back to Gong and Shou's reunion. Gong properly handled the safety hazards in the laboratory, but he became interested in Shou's life that he glimpsed at that moment, and slowly got involved... Mission: Cherish life and abide by safety regulations.