The Seventeen clip is kinda scary, not because something scary happens or because they saw a ghost or something, but because there was a random person on set that no one knew about. Thats pretty scary since we don't know what her intentions are for hiding there. It might ofc all be planned by the staff, but Vernon seems to realize quickly that the girl isn't in on it. If it was a crazy fan who knows what she might have done. Either it's planned by the staff, or their security is not good enough.