An Officer and a Gentleman

Zachary "Zack" Mayo (Richard Gere) has been living in the Philippines with his womanizing father Byron (Robert Loggia), an alcoholic U.S. Navy chief boatswain's mate, since early adolescence, after Zack's mother committed suicide when Zack was around 10-years-old. Hoping to put his life on a different path, Zack signs up for the Navy's Aviation Officer Candidate School (AOCS) to become a Navy pilot. In the opening scene, Zack tells Byron about his intentions. But Byron doesn't offer much support or compassion. He tells Zack that U.S. Navy volunteers must serve six years before becoming a Navy jet pilot. After saying goodbye to his father, Zack packs up and leaves his father's decrepit Seattle apartment and rides away on his motorcycle to his destination.Opon arrival at the U.S. Navy Cadet Training Camp located outside Tacoma, Washington state, Zack and his fellow AOCs are "welcomed" by their strict head drill instructor, Marine Gunnery Sergeant Emil Foley (Louis Gossett, Jr.). Foley makes it clear that the program is designed to eliminate any officer candidates who are not suitable to earn their "prize"; a commission as an ensign in the U.S. Navy and flight training worth over $1,000,000 a year in salary. Foley further warns the male candidates about the young women in the area, who Foley says scout the regiment for officers that they want to marry and will go so far as to feign pregnancy or actually become pregnant in order to trap them. Zack hits it off with two fellow outgoing candidates, Sid Worley (David Keith) and female candidate Casey Seeger (Lisa Eilbacher).A few days later, Zack and Sid meet two local girls - factory workers - at a Navy-hosted dance. Zack begins a romantic relationship with Paula Pokrifki (Debra Winger) and Sid with Lynette Pomeroy (Lisa Blount).Meanwhile, Foley rides Zack mercilessly, believing that he lacks motivation and is not a team player. When Zack's side business of selling pre-shined shoes and belt buckles is discovered, Foley hazes him for an entire weekend in an attempt to make him DOR ("Drop on Request", AOCS term for requesting termination of one's training), but Zack refuses to give in. Foley then tells Zack that he will simply have him thrown out; Zack finally breaks down, telling Foley that he has nowhere else to go and has nothing else in his life. Satisfied that Zack has come to a crucial self-realization, Foley lets up on him.While Zack and Paula spend the next weekend together, she takes him home to meet and have dinner with her family. After dinner, she shows Zack an old picture of her real father. He was also an AOC who, following his commissioning, left for flight training and simply deserted her mother, refusing to marry her when she became pregnant with Paula. Zack lies about his life by telling Paula that his father is dead.Later, Zack has a chance to break the record time for negotiating the obstacle course; meanwhile, Seeger will be disqualified if she can't negotiate the 12 foot high wall. which she lacks the upper-body strength to climb easily. Zack abandons his attempt to break the course record in order to coach Seeger over the wall, and she makes it.Following dinner with Sid and his parents in town, Zack learns that Sid has a long-time girlfriend back home, whom he plans to marry after being commissioned. Meanwhile, Lynette has been dropping hints to Sid that she may be pregnant. During a high-altitude simulation in a pressure chamber, Sid has a sudden anxiety attack. Realizing that he joined up out of a sense of obligation to his family, Sid DORs, and then leaves the base without saying goodbye, so Zack and Paula go out to look for him.Sid goes to Lynette's house and proposes marriage to her. She turns him down, but not before confessing she wasn't pregnant. She wanted him to graduate in order to fulfill her dream of marrying a Navy pilot, and all but curses him for dropping out. She is later cursed by both Zack and Paula when they come to see her about Sid's whereabouts. Despondent over Lynette's rejection, Sid checks into a motel and commits suicide.At the climax, Zack decides to DOR himself but Foley won't let him go so close to graduation. He and Zack clash in an unofficial martial arts bout with the platoon looking on. Although Zack dominates for most of the fight (mostly fueled by his anger at Foley, who he believed played a part in Sid's suicide by not stopping him from leaving), Foley manages to win by kicking Zack in the groin. Foley tells him he can quit if he wants to.Zack does show up for graduation, and is sworn into the Navy with his class. Following naval tradition, he seeks out and receives his first salute from Foley in exchange for a US silver dollar. While tradition calls for the drill instructor to place the coin in his left shirt pocket, Foley places the coin in his right pocket and gives Zack a picture-perfect salute, acknowledging that Zack was a special candidate. Zack tells him he will never forget him and that he never would have made it through without his guidance. Zack then leaves the Navy school on the same motorcycle he arrived on.In the final scene, Zack, now Ensign Mayo with orders to flight training, seeks out Paula at the factory where she works. He picks her up and walks out with her in his arms to the applause and cheers of her co-workers, including Lynette.

Question: Why did Lynette turn down Sid's marriage proposal?
Answer: Why did Lynette turn down Sid's marriage proposal?