Moreland, aware that a scandal over the black doctor's actions could endanger funding, denies the request in the hope that the incident will be forgotten. Upon learning from police records that Johnny was married, Wharton and Luther visit his widow, Edie Johnson, who tells the doctors that she divorced Johnny a year and a half ago, and that she hates his whole family. Although she does not reveal it to Wharton, his sympathetic attitude persuades her to visit Ray to ask about the autopsy. Ray tells her, however, that Johnny would be alive if he had had a white doctor, and that Wharton wants to have the autopsy to cover up the truth about Luther's actions. Edie's racist feelings are revived by Ray, with whom she had committed adultery, and he convinces her that Wharton played her for a "chump," and that she can make up for her past infidelity to Johnny by contacting Beaver Canal club owner Rocky Miller and telling him about Johnny's death. Accompanied by Ray's other brother George, who is a deaf-mute, Edie goes to the club, where Rocky and his pals lay plans to attack the black section of town, which they call "Niggertown." Although Edie desperately wishes to leave, Rocky forces her to stay. Meanwhile, Luther arrives at the hospital and learns about the upcoming attack from Lefty Jones, a black elevator operator. Luther tries to dissuade Lefty from organizing a counterattack, but Lefty reminds him of a race riot that occurred while Luther was away at school, during which Lefty and his sister were beaten. Luther then contacts Alderman Tompkins to try to avert the riot, while Lefty and a large group of blacks, including Luther's brother-in-law John, meet and plan their strategy. Edie watches in disgust as the whites prepare their weapons, but leaves before the blacks surprise the whites by attacking first. As victims of the riots are brought in to the hospital, Wharton is called in from home. Before he departs, however, a drunken and disheartened Edie arrives at his house, and Wharton leaves her in the care of his black maid, Gladys. Although Edie fears that Gladys will harm her because of her connection to the riot, Gladys tenderly cares for her when she collapses.
At the hospital, Luther tends to the victims until a white woman orders him to take his "black hands" off her son. Stunned, Luther walks out, and the next morning, after Wharton returns home to find Edie chatting with Gladys, Luther's wife Cora arrives and announces that Luther has given himself up to the police for the murder of Johnny Biddle. Cora relates that after he left the hospital, Luther realized that the coronor would be forced to conduct an autopsy if he were charged with murder. Wharton assures Cora that he will stand by Luther, and after he leaves with Edie, Cora's stoic demeanor in front of the whites crumbles and she cries in Gladys' arms. Following the autopsy, the coroner confirms that Johnny died of a brain tumor and that Luther was justified in performing the spinal tap. Wharton, Cora and Edie are pleased that Luther has been exonerated, but Ray insists that the doctors are conspiring to bury the truth. Luther leaves with Cora, following by Edie, who denounces Ray before she departs. After overhearing Wharton tell the coroner that he is leaving town for a much-needed rest, Ray and George overpower the police guard and escape. When Edie returns to her apartment, she finds Ray and George waiting, and Ray, whose leg is bleeding profusely, beats Edie to make her call Luther and tell him to meet Wharton at his house. Drunk and in shock, Ray raves that he is going to kill Luther, then leaves Edie with George. By turning up the volume on her radio, which George does not notice, Edie cause her neighbors to break down her door, then escapes and calls the hospital prison ward for help. Meanwhile, when Luther enters Wharton's house, Ray holds a gun on him, beats him and shouts racist slurs. Edie arrives and tries to stop Ray from killing Luther, but Ray's physical pain and obsessive hatred have pushed him beyond reason. Edie turns out the lights as Ray shoots at Luther, and although Luther is wounded in the shoulder, he retrieves Ray's gun as he collapses in pain. Edie coldly tells Luther to let Ray's leg bleed, but Luther asserts that he cannot kill Ray simply because of his racism, then uses the gun and Edie's scarf to fashion a tourniquet. As a siren announces the arrival of the police, Luther tells the hysterical Ray, "Don't cry, white boy, you're gonna live."
Poitier and Widmark struck up an immediate friendship and respectful partnership, with Poitier dubbing the actor "the most pleasant and refreshing surprise in my initial exposure to the Hollywood scene. The reality of Widmark was a thousand miles from the characters he played." In fact, the relationship was so respectful that Widmark felt compelled to apologize after each take in which he mistreated Poitier, both verbally and physically.
Twentieth Century-Fox purchased the motion picture rights to Lesser Samuels' original story in Jan 1949 and signed him to a ten-week contract to write the screenplay. Paramount, Universal, Warner Bros. and Columbia were also advocating in bidding for the rights.
Samuels, in a New York Times article dated back from July 1950, stated that he originally wanted to write about "the cancerous results of hatred," but did not intend to focus on an African-American doctor until he learned from colleagues of his daughter's fiancé, a doctor, about the problems faced by African-Americans doctors.
The script originally ended with Luther being killed, a rough climax that studio chief Darryl F. Zanuck actually liked. Zanuck would later express disdain for the ending, realizing audiences, "would be left with a feeling of utter futility. Luther, a wonderful character, is hideously slaughtered. If his death resulted in something, if something were accomplished either characterwise or otherwise, it would be different and I would accept it." Mankiewicz prepared a new preliminary script, with a new storyline and characterizations, which was ultimately given the greenlight by Zanuck.
No Way Out marked the screen debut of Ossie Davis, and was the first film in which Davis appeared with his wife, Ruby Dee.