For Xiao, this world is her dream. She is dreaming. The dream belongs to a parallel world. If she "wakes up" in the original world, she will disappear in this world...
Xiao played with the attitude of the world until he finally fell in love with Jiang and told Jiang the truth. Then he was afraid of losing Jiang because for Xiao, she could not control the time of waking up and her disappearance was unknown.
Mission: Caring for mental health