In "Hearts and Hands," in what way does O. Henry's choice to use a surprise ending allow readers to see story details in a new light after finishing the story?

In the short story "Hearts and Hands," the author O. Henry suprises readers when at the end of the story two passangers acknowledge Mr. Easton is not the marshall but the counterfeiter, as he has deceived Miss Fairchild with the real marshall's complicity. Thus, O. Henry intends to cause amazement and mislead readers in the same way Mr. Easton misleads Miss Fairchild.