Berenger endures a nightmare in his room (the room bears a striking resemblance to Jean's). He wakes, takes off a bandage from his head, and inspects his forehead for a sprouting rhinoceros horn. Still human, he nearly pours himself a drink, but he reprimands his weakness and puts the glass down. After hearing rhino noises from outside, he shrugs and drinks it down. He coughs and fears that he's metamorphosing, but a comparison between his cough and the sound of the rhinos outside allays his anxieties. He lies down again.
Dudard knocks on the door, and Berenger lets him in. Berenger fearfully asks if his voice has changed, for it seems as though Dudard's has. Dudard denies both accounts, and Berenger agrees that he was incorrect. His paranoia augments as he inquires if he has a bump, which he doesn't. They discuss Jean's transformation, which Berenger feels guilty about, thinking Jean chose to change specifically in his presence. Dudard reprimands his solipsism, and Berenger agrees but asks for an explanation for the metamorphoses, which Dudard admits he does not have. Berenger says he would want to stay himself no matter what, but is still afraid of "catching" the "disease." Dudard suggests Jean was primed for the change by his excitable personality, and Berenger seizes upon this notion: Jean, and perhaps the others, were "temporarily unbalanced," in a "critical condition."
They discuss the metamorphoses as an epidemic. Dudard believes it is temporary and even beneficial. Berenger wonders if he is immune, then states with certainty that if one doesn't want to catch it, then one won't. He takes another drink under the premise that alcohol is an immunization. Berenger coughs from the alcohol and again worries over an impending metamorphosis. Dudard recommends that Berenger stop drinking if he is to have will-power, but Berenger argues that his decision to drink is a deliberate one. Dudard points out that Berenger is making excuses, and Berenger assents.
Berenger continues to take responsibility for the metamorphoses, and Dudard urges him not to involve himself too much. Berenger says that if he were to read about an epidemic in another country in the newspaper, he could maintain an objective detachment, but "when you're involved yourself you can't help feeling directly concerned." Dudard says he's getting used to it and recommends walks and sleeping pills, which Berenger rejects. Dudard says must accept whatever reason there is for the rhinos, which Berenger denounces as fatalism. They continue to argue about how much involvement one should have. Dudard contends that any anxiety Berenger is having is related to his own fears of turning into a rhino—which Dudard claims won't happen, because Berenger doesn't have the "vocation" to become one. They discuss office matters; Dudard is annoyed at the workmen, assigned to repair their office staircase, who seem to disappear after a few days.
Dudard reveals that Papillon has resigned—and turned into a rhinoceros. Dudard finds this humorous, while Berenger is upset and wonders why he would do it, since he held such a powerful position. If this is the case, then the metamorphosis must have been involuntary: "He let himself be talked into it." They discuss Botard, and Dudard explains why he doesn't like the old skeptic—despite the force of Botard's convictions, Dudard finds his logic imprecise and subjective. Dudard considers the metamorphoses natural, while Berenger continues to find them "abnormal." Berenger, flustered in the face of Dudard's supreme intellect, says he will seek the Logician's services in clearing this up. As they discuss him, a herd of rhinos passes and Berenger spots the Logician's hat on a rhinoceros, a sure sign of the Logician's metamorphosis, and vows not to become one as well.
The strength of Berenger's will vacillates. Though he ends this section with a decisive statement, and earlier makes a strong declaration of free will (if one doesn't want to catch the disease, one won't), his resistance to alcohol continues to waver. Claiming his decision to drink is a premeditated one, he exposes a complex, circular dilemma: is the conscious decision to remove rational decision-making abilities (here, to choose consciously to escape into unconsciousness through drinking) a conscious choice after all? Extended to the extreme, this sentiment asks whether suicide is a viable form of confronting death. This was the ultimate preoccupation of existentialist philosophers, especially Martin Heidegger and Jean-Paul Sartre. Or is suicide a cowardly act that removes true commitment and recognition of absurdity, of confronting death while still alive? Dudard's accusation, that Berenger is trying to rationalize his cowardice, affirms the existential view that confrontation with death is a constant, lifelong struggle, not a temporary one like the momentary act of suicide.