Katharine Clifton first dreamed of the man who would become the English patient several days after she met him. She woke up screaming as if from a nightmare and Geoffrey brought her a glass of water. In her dream she had felt the man's anger toward her, his frustration that a married woman was among them. In her dream he had "yoked her neck back so that she had been unable to breathe within her arousal." Most of what she felt toward him was sexual. While he rambled, she longed to slap him, though she listened politely. She had plenty of time to study him, this man who had years earlier left normal life for the world of the desert.
The man angers Katharine with his assumptions and his excessive politeness. Nonetheless they begin a love affair and soon cannot bear to be apart from one another, sneaking private moments in plum gardens, crowded markets, and offices. She is confused about what to do, as she hates a lie but knows that Geoffrey will go mad if she tells him about her affair. Katharine takes her frustration out on the English patient, making various colors of bruises on his skin with her blows, throwing plates at his head, and stabbing forks into his shoulder. He makes up silly excuses for his wounds, and people start to think he is quite accident-prone.
The love affair is tumultuous. The man, who has never felt alone even in the desert, cannot bear to be without Katharine. He wishes to "burn down all social rules, all courtesy" to get to her. He knows that they are "sinners in a holy city" but does not care, as long as he can remain with her. In public, she builds a wall between them, refusing even to look at him or acknowledge him. This drives him mad, but he knows Katharine does it for her own protection, as he has protected himself emotionally from the outside world for so long. He tries to work but he can hardly write. He goes insane if he is not with her, and he cannot accept losing her.
One night, the twenty-eighth of September, Katharine decides she cannot compromise, and insists that they be apart. She tells the man that they can never see each other again, as her husband, Geoffrey, will go mad if he finds out. The man brings Katharine home, unsure whether Geoffrey is inside. He tells her he does not miss her yet, but she says that he will. He feels he has fallen in love and been disassembled.
Chapter V is like the other chapters in that it is not chronological, but is unlike some of the others in that it has a unifying theme: the English patient's passion for Katharine. Their love, which begins as purely physical, quickly progresses to something much deeper. This conflation of the physical body with the emotional existence is a recurring idea in the novel. The English patient's connection to Katharine transcends the physical, and he feels insane when he is not with her. She is so constantly in his thoughts that he is unable even to work. Her emotional and psychological presence becomes so foremost in his mind that he is shocked to be brought back to reality with a reminder of physicality—a vaccination scar on her arm. Ondaatje perhaps mentions the otherwise insignificant scar to highlight the physical and emotional depth of Katharine's relationship with the English patient.
The physical wounds the English patient endures at Katharine's hand are also significant. Her abuse of him suggests that love and hate are closely intertwined emotions. When two people who have been extremely accustomed to existing alone suddenly connect, abandoning their self-sufficient worlds, they find it shocking and upsetting to discover their reciprocal need for another person. Katharine especially struggles because this person she has discovered a need for does not fit nicely or neatly into her life. This is what Katharine discovers, and she hates her lover for it. What emerges from this chapter is an overriding sense of extreme, even uncontrollable passion. Ondaatje portrays a passion for which the characters would sacrifice their entire existence.