during a tea party that her husband, Brian, may have had an affair with Clare. Brian’s suspicious and telling behavior when the two speak privately in their room is one indication that he has been secretly nursing feelings for Clare without Irene’s knowledge. Irene’s suspicions are only further exacerbated when she joins the party in the other room. Clare, it seems, had a way of beguiling even the most intelligent men with her seductive mannerisms. As Larsen describes,
And all because Clare had a trick of sliding down ivory lids over astonishing black eyes and then lifting them suddenly and turning on a caressing smile. Men like Dave Freeland fell for it. And Brian.
The thought that Brian, too, might have become smitten by Clare because of her elegant appearance sickens Irene to the core.
In the second chapter of the third part, Irene begins to question her earlier assumptions regarding Brian’s infidelity. She assures herself that they were founded on nothing but her own paranoia and a baseless narrative she had manufactured in her head. There was no hard evidence, after all, that directly implicated Brian in any wrongdoing, as Clare reasons:
With this self-assurance that she had no real knowledge, she redoubled her efforts to drive out of her mind the distressing thought of faiths broken and trusts betrayed which every mental vision of Clare, of Brian, brought with them.
What we, the readers, can see at this point is that Clare’s constant presence in Irene’s life is causing her immense psychological stress and is eroding her self-confidence. At this point, regardless of whether Brian is or is not guilty of infidelity, and whether Clare is the cause, Irene wants to get her out of her life as quickly as possible. Throughout the novel, but particularly after she came to visit her friend in New York, Clare has been nothing but a source of worry for Irene. Even though she holds Clare to be among her closest friends, the pressure of the situation is becoming to much for Irene to bear:
Though she had come almost to believe that there was nothing but generous friendship between those two, she was very tired of Clare Kendry. She wanted to be free of her, and of her furtive comings and goings.
All of this psychological torment had been building up in Irene’s mind up to the last, climactic moments of the novel’s conclusion. Throughout the dinner party, Irene takes notice of how upbeat, flirtatious, and positive Brian becomes in the presence of Clare, and the seductive way in which Clare takes Brian’s arm to avoid slipping on the ice. Brian’s words to her earlier, when the two had yet another disagreement in their kitchen about Irene’s refusal to move to Brazil, suddenly take on renewed significance:
“Don't expect me to give up everything," repeated themselves. What had they meant? What could they mean? Clare Kendry?
Finally, Clare’s husband, John Bellew, bursts into a gathering and reveals that he knows that Clare is black. In the commotion, Irene reaches out for Clare, who is standing by a window. The scene reads:
She ran across the room, her terror tinged with ferocity, and laid a hand on Clare's bare arm.
In sum, these combined instances of self-doubt, passionate rage, suspicion, and mental anguish had culminated to a breaking point, which finally burst whenever John Bellew broke up the monotony of the dinner party. In my interpretation, Bellew’s paroxysm provided the stimulus that Irene needed to finally push her from indecision to activity. The fact that she lays a hand on Clare’s arm at the exact moment that Clare falls could be an indication that she was trying to save her life. However, given everything that had transpired up to that point—Irene’s revelation that Clare and Brian were having an affair, the continuous arguments between Irene and her husband, the fact that Clare had still not departed the city and was acting like an anchor on Irene’s life, John Bellew’s crashing of the party—I think it is more likely that Irene pushed her friend to her death.