Back in Prague, Tomas can’t sleep due to the sounds of Russian airplanes circling the night sky. He thinks back to when he first fell in love with Tereza, and she told him that if she hadn’t fallen in love with him, she would have fallen in love with another man, one of Tomas’s friends. It was chance, Tomas thinks, not fate that has brought them together. In fact, Tomas and Tereza’s meeting had involved a total of six “chance happenings.”
Tomas’s “chance happenings” are exactly what Tereza sees as fate, which again underscores the ambiguity of language; the seemingly opposite words can apply equally to the same situation. This passage also underscores Tomas’s doubt—he is worried that he sacrificed his future for a mere coincidence, not true love.
Tomas has returned to Prague because of Tereza, and the need to make such a heavy decision would not have existed if not for his colleague’s sciatica. Tomas was sent to Tereza’s small Czechoslovakian town because his colleague could not go. If not for someone else’s sciatica, Tomas thinks, he would have never met Tereza in the first place. Thinking this, Tomas feels no compassion for Tereza. He feels only despair over having returned to Prague.
Tomas has sacrificed his power and freedom by returning to Prague, and he clearly resents Tereza for his decision to return—even though she did not pressure him to do so. Tomas’s reason for going to the small town, where he subsequently met Tereza, was completely random and coincidental, which suggests that he was not destined to be with Tereza after all.