Tereza puts the crow in a bed of old rags on the bathroom floor. She sees in it a reflection of her own fate, and knows that she has no one except Tomas.
The narrator asks what Tereza learned from her escapade with the engineer. Did she learn that casual sex is light and weightless?
Nope. She can't get her mind off the scene when she came out of the bathroom and wanted the man to call to her soul.
She wonders what would have happened if Tomas and one of his mistresses had been in the same situation. Tomas would have said a single word, and the woman would have been his for the taking.
Tereza knows how it works, "the moment love is born: the woman cannot resist the voice calling forth her terrified soul; the man cannot resist the woman whose soul thus responds to his voice" (4.21.6).
She knows that Tomas is defenseless against the lure of love.
Tereza has no weapons but her own fidelity, which is the cornerstone of their relationship.
She finally leaves the crow for a moment to get a bite to eat.