Why is franton nuttel so frightened in the open window?

Frampton Nuttel is frightened in "The Open Window" because he is confronted by a seemingly ghostly figure—Mrs. SAppleton's husband and brothers—who he believes have died in a tragic hunting accident. His anxiety is compounded by the eerie story told by Mrs. SAppleton's niece, Vera, who crafts a tale about the family's supposed tragedy, making Frampton feel vulnerable and unsettled. The sudden appearance of the men, who he thought were dead, triggers his panic and ultimately leads him to flee in terror.