Dongyang doesn't know how long he can live, and he doesn't want to live that long. He doesn't want others to care. He even hopes that everyone will turn into goldfish like the little girl. After 7 seconds, he will no longer mourn for death.
He knows that this is impossible, just like it is impossible for him to spend this life safely. He knows that this will definitely cause trouble to the people around him, so why not let everyone die, everyone, is this okay?
"What do you think, Dongyang?"