During those two beautiful days of melancholy, his compassion (that curse of emotional telepathy) had taken a holiday. It had slept the sound Sunday sleep of a miner who, after a hard week's work, needs to gather strength for his Monday shift.

This curious melancholic fascination lasted until Sunday evening… On Monday, everything changed. Tereza forced her way into his thoughts: he imagined her sitting there writing her farewell letter; he felt her hands trembling; he saw her lugging her heavy suitcase in one hand and leading Karenin on his leash with the other; he pictured her unlocking their Prague flat, and suffered the utter abandonment breathing her in the face as she opened the door.

Instead of the patients he was treating, Tomas saw Tereza. He tried to remind himself. Don't think about her! Don't think about her! He said to himself, I'm sick with compassion. It's good that she's gone and that I'll never see her again, though it's not Tereza I need to be free of -- it's that sickness, compassion, which I thought I was immune to until she infected me with it.

He kept warning himself not to give in to compassion, and compassion listened with bowed head and a seemingly guilty conscience. Compassion knew it was being presumptuous, yet it quietly stood its ground, and on the fifth day after her departure Tomas informed the director of his hospital (the man who had phoned him daily in Prague after the Russian invasion) that he had to return at once.

He was ashamed. He knew that the move would appear irresponsible, inexcusable to the man. He thought to unbosom himself and tell him the story of Tereza and the letter she had left on the table for him. But in the end he did not. From the Swiss doctor's point of view Tereza's move could only appear hysterical and abhorrent. And Tomas refused to allow anyone an opportunity to think ill of her.

On Saturday and Sunday, he felt the sweet lightness of being rise up to him out of the depths of the future. On Monday, he was hit by a weight the likes of which he had never known. The tons of steel of the Russian tanks were nothing compared with it. For there is nothing heavier than compassion. Not even one's own pain weighs so heavy as the pain one feels with someone, for someone, a pain intensified by the imagination and prolonged by a hundred echoes.

Tomas shrugged his shoulders and said, Es muss sein. Es muss sein.

The allusion was even more pertinent than he had thought because the Swiss doctor was a great music lover. Smiling serenely, he asked, in the melody of Beethoven's motif, Muss es sein?

To make the meaning of the words absolutely clear, Beethoven introduced the movement with a phrase, Der schwer gefasste Entschluss, which is commonly translated as the difficult resolution.

It was an allusion. The last movement of Beethoven's last quartet is based on the following two motifs:

The director of the hospital was in fact offended.

This allusion to Beethoven was actually Tomas's first step back to Tereza, because she was the one who had induced him to buy records of the Beethoven quartets and sonatas.

Ja, es muss sein! Tomas said again.