Hmmmm I’m not really sure but I think the golden apple represents the baby. Remember wooyoung dreamt that he wants to eat it with the kyungju, I think he meant that he wants to have a baby with kyungju, since kyungju bacame really scared right and wooyoung said that he and the baby doesn’t need a coward father. So in conclusion wooyoung wants to have the baby and want kyungju to be there through the hardships of pregnancy.

lmaoo can someone explain the apple analogy for me