Why does Framton Nuttel leave in such a hurry and how does Vera explain it?
In "The Open Window," Framton Nuttel flees in terror from what he probably believes are ghosts, but Vera credits his flight to a fear of dogs.
Vera, a fifteen-year-old girl whose name hints at truth (veracity), is sent to entertain Framton Nuttel, an unexpected guest who informs the young lady that he has letters of introduction for Mrs. Sappleton, her aunt. After cleverly getting Nuttel to reveal that he does not know people from the area and is not familiar with the area itself, the girl immediately launches into her tale of half-truths about the hunting venture of Mrs. Sappleton's husband and two brothers that ended in tragedy "three years ago to a day." As Vera completes her tale, she shudders slightly.
To Framton's relief, Mrs. Sappleton enters the room, apologizing for her delayed appearances. But Framton is immediately unnerved when her words underscore Vera's observation that her aunt still believes her husband and brothers will return. Mrs. Sappleton explains that she has the window open so that the men will avoid her carpets as much as possible by entering through the open window after they have traversed the marsh and gathered mud and such on their boots.
Further, as Mrs. Stappleton "rattles on cheerfully about the shooting and the scarcity of birds," Framton finds the conversation "all purely horrible." The nervous man tries to steer the talk away from the ghastly topic, thinking that it is most unfortunate that he has arrived on this tragic anniversary. Still keeping one eye on the window, Framton makes a desperate attempt to change the topic of conversation by again explaining his medical condition and adding that his doctors have ordered him not to do anything that excites him.
Suddenly, however, Mrs. Stappleton breaks in and cries out, "Here they are at last!" In the dim light of early evening, three figures who match Vera's previous descriptions approach, carrying guns. A brown spaniel is at their heels. As they draw closer, Framton hears the youngest say exactly what Vera quoted earlier, "I said, Bertie, why do you bound?"
Believing that these figures must surely be ghosts, Framton Nuttel "grab[s] wildly at his stick" and flees the house, running down the gravel drive and out the front gate. As Mr. Sappleton enters through the window, he asks, "Who was that who bolted out as we came in?"
"A most extraordinary man. A Mr. Nuttel," said Mrs. Sappleton.... "One would think he had seen a ghost."
"I expect it was the spaniel," said the niece calmly; "he told me he had a horror of dogs...."
Glibly, then, Vera launches into another of her "romantic" tales.
Mr. Nuttle leaves in a hurry because he is frightened. Vera has told him a story about why Mrs. Sappleton leaves the window open, saying that Mrs. Sappleton believes her missing husband and brother will return thought it, just as they left through it, seemingly long ago. Although the story is not true (the men only left that morning), Mr. Nuttle, a very nervous guy, believes it. Therefore when the men do return through the window, Mr. Nuttle suffers a "nervous breakdown" and must flee.
Nuttel leaves in a hurry because fear is the only emotion he understands. We learn that he is a nervous person, who does not like strangers. The idea that he even believes Vera's story suggests weakness. Nuttel has obviously dealt with fear and anxiety for so long it has become a second nature to him. Nuttel never thinks about questioning Vera's story, he just reverts to the only emotion he is capable of executing with certainty, which is to run away.