Challee examines the two psychiatrists who examined Queeg on the Ulithi Atoll. With complete confidence, these psychiatrists pronounce Queeg fit for command. They admit to his abrasiveness, and perfectionism, but conclude that these problems were not serious, and even possibly beneficial. In his cross- examinations, however, Greenwald tricks the psychiatrists, forcing the first doctor to admit that Queeg has symptoms that fit the profile of a paranoid personality disorder. The psychiatrist is forced to admit that in extreme pressure, Queeg's problems might have become disabling. Greenwald tricks the second psychiatrist, a Freudian, into admitting that Queeg was "sick." Greenwald also draws the doctor into revealing a dislike of all military types and a conviction that craziness is a requirement of command. Greenwald then discredits the psychiatrist's expertise, for the doctor never served aboard a ship. Challee tries and fails to get the doctor to retract the word "sick" from his statement.
The prosecution rests, and it is the defense's turn to call witnesses. Greenwald announces that he will only call two witnesses, the first being the accused. Maryk takes the stand and Greenwald asks him to recount the events of the day of typhoon. Maryk does so honestly, painting a picture of Queeg frozen by terror and stubbornness. Maryk talks about some of the debacles described in his journal. Maryk explains how Queeg offered to forget the mutiny and have the penciled logs changed so that both of their military careers would be saved. Maryk refused the offer, and Queeg pleaded with him. Maryk proves that he was calm during the typhoon by pointing to his perfect rescue of the survivors of the George Black. He states that he removed the captain from command with full intent, and believed he was justified in doing so.
Challee cross examines Maryk with hostility, trying to establish that Queeg was still giving commands after the mutiny. Maryk explains that the captain often made commands only after Maryk had already given the orders. Challee attacks Maryk's loyalty, and is surprised when Maryk admits that his handling of the Stilwell telegram had been disloyal. Challee cannot establish a pattern of disloyalty, however, as Maryk is able to say truthfully that he was never disloyal again. Challee tries to establish that Maryk does not understand psychology. Maryk admits that he did not understand the science, but was sure that the captain was sick while on the bridge in the typhoon.
Greenwald calls Queeg to testify. Greenwald asks if Queeg offered to erase the logs, as Maryk claims. Queeg denies it. Greenwald says the incident comes down to his word against Maryk's, and Queeg stakes his long history and reputation to his word. With a trap in place, Greenwald then asks whether the box Willie lost overboard was full of liquor, and Queeg immediately denies it. When Greenwald offers to produce evidence that it was full of liquor, Queeg invents a story about a second crate. Everyone is sure the jury sees through this lie. Greenwald vehemently denies making Willie pay for the liquor, but his credibility is destroyed, and he is reduced to insulting Keith.
Greenwald questions Queeg about the towline cutting incident. Challee objects harshly, but the objection is overruled. Queeg says he saw guns firing close by and ordered the helm to turn. Greenwald asks the captain to cite a sailor who could confirm the existence of gunfire. Queeg begins to show nervousness. His stress increases as Greenwald asks the dye marker incident. Greenwald asks if Queeg got ahead of the boats, dropped a marker, and then ran. Challee objects, but Blakely steps in. He forces Queeg to admit that there was no reference to a dye marker in the mission orders. It becomes obvious that Queeg is lying and that Blakely has become doubtful.
Blakely asks about the Stanfield straddling, questioning Queeg about his seemingly cowardly behavior. Queeg invents an extravagant set of circumstances that the jury sees right through. They talk about the mutiny, and Queeg becomes increasingly agitated. He admits that he planned to abandon fleet course, and then pulls the two steel balls out of his pockets and begins rolling them. Queeg destroys his original statement and the pillar of the prosecution's case by admitting to his plan to abandon fleet course, for that is what Maryk actually did, and the prosecution was trying to prove that abandoning fleet course was wild and irresponsible. Queeg's answers become increasingly disorganized, meaningless, and contradictory.
In his closing arguments, Challee argues that Article 184 was misused, for Queeg was not completely and irrefutably insane. Greenwald simply goes over the facts and the inconsistencies in Queeg's testimony, leaving it to the court to decide. The court takes only one hour and ten minutes to acquit Maryk of all charges. Afterward, Keefer has a celebration organized and paid for by the presale of his novel. Greenwald is the guest of honor, and he arrives late. In a speech, Greenwald praises Keefer and his novel, but then lays into Keefer, saying it was the Queegs of the regular Navy who saved Greenwald's grandmother from Hitler. He says he took advantage of the captain's stupidity and the two pompous psychologists to get Maryk acquitted. He says Keefer authored the mutiny and then left his friend out to dry. He leaves, and the party dies off.
Greenwald discredits the testimony of the psychiatrists by focusing on the fuzzy semantics of what it means to be "sick." He forces the second psychiatrist to confirm that Queeg was sick in the way that everyone is sick, and then uses this meaningless label to throw suspicion over the entire psychological investigation. The crucial testimony of Willie Keith also helps Maryk. His testimony is not actually relevant, but it appeals to Naval pride, which abhors a coward. The Navy men on the jury do not like to think that a coward was commanding one of its ships. Greenwald could rely on the jury's automatic dislike of Queeg to help him recreate a situation in which Maryk was justified in relieving Queeg of command. In his examination of Queeg, Greenwald simply makes the captain look stupid, and then Queeg's paranoia does the rest. By the time the lawyer comes to the typhoon, the captain is so rattled he has nearly returned to the panicked state in which he commanded the Caine. Everyone in court begins to realize that there is something wrong with Queeg. The turning point comes when Queeg pulls out the steel balls, his constant security blanket. This odd gesture tells the jury everything it needs to know. Compared to Queeg's unraveling, Maryk's simple, steady testimony, with its correct references to the ship's position and heading, seems like scripture.
Greenwald's interruption of the acquittal party completely changes the direction of the novel. For thirty-six chapters, Willie sails upward through naval life, and we envision the Navy as a provider of the maturation process Willie experiences. Then, at the acquittal party, we learn that the purity Willie sees in the Navy is no more pure than civilian life. Until the party, Willie thinks of himself as playing a righteous and patriotic role on the Caine. At the party, he begins to discover that he was sucked into the scheme of a moody, oversensitive intellectual, a scheme that undercut all that is good about the Navy. Willie was corrupted by his time under Queeg. While testifying, Willie realizes that he based his actions on personal prejudice, not on the safety of the ship.