Mong Jung Mong (몽중몽)/theories

Lee Jin Hui's Family and her Amnesia
Three special NPCs, who we'll be calling Helper/Ani, Friendly Person/Gidae and Doctor/Gyosu (Seen in the lab of the Non-destroyed town) are members of her former family. Gidae consoling Jin Hui throughout her childhood, Gyosu being some sort of scientist. Judging by this info and fact that Gidae and Gyosu have the same hair color as Jin Hui's, they could potentially be her mother, father and Sister, but why she can't remember anyone of them and especially mother's face? During whatever apocalyptic event went down, Jin Hui got some form of amnesia (Maybe the "Certain Incident" mentioned in the text after the "Go Outside" event), which is why she can't remember her close relatives' or friends' faces or names. Which may be why the Faceless gray-haired NPC had no face, why most of the students within her school have no face or distinct features outside of gender, or why the Red-haired girl was a silhouette until Lee used her School uniform effect.