Why does William Kane not leave the town in high noon?

In "High Noon," William Kane chooses not to leave the town because he feels a strong sense of duty and responsibility to confront his past and protect the townspeople from the impending threat. Despite the fear and danger posed by the arrival of Frank Miller and his gang, Kane believes that running away would betray the values he stands for and the trust placed in him as the town's marshal. His commitment to justice and moral integrity ultimately compels him to stay and face the confrontation head-on.