How does the old crone exact her revenge on the world in the book, Whale: A Novel?

When the old crone is saving her money, she promises to use it to exact revenge on the world. However, she dies before spending her fortune. Years later, when Geumbok discovers the cache of money, she begins building new businesses, including the movie theater. When the theater is packed with people, the ghost of the old crone locks the exits. Geumbok drunkenly drops a lighter and sets the cinema on fire. While the old crone is not alive, she exacts revenge on the world by killing hundreds of peoples. The money she saved directly leads to the fire and, later, the ruin of Pyeongdae.