Why is the Rum Gone

In the movie, Captain Jack Sparrow and Elizabeth Swan both end up stranded together stranded on a deserted island in the middle of the Caribbean Sea. Jack, who is already familiar with the location, reveals to Elizabeth that there is a hidden storeroom filled with rum under the island. After Jack drunkenly falls asleep, Elizabeth uses the rum to torch the whole island with the aim to give out signals to nearby ships. Once Jack wakes up, he realizes that there is nothing left on the island and confusedly asks: “But why is the rum gone?”