Anger arises from delusion and perpetuates delusion. But the source of delusion is conceit rooted in the ignorance I am.

The student in the parable makes the common mistake of failing into nihilistic views. If the I am conceit is empty of a separate self. If the I am conceit is changing and empty. Then it doesn't exist. It is nothing.

But the Buddha said in my favorite sutra that the point is not to be caught by the I am conceit. To not even give rise to the thought I exist or I do not exist. Essentially, to overcome the attachment to I making completely and stop trying to work out questions like is it or is it not.

The Buddha continued, “If, when he considers the six bases for wrong views, a bhikshu does not give rise to the idea of ‘I’ or ‘mine,’ he is not caught in the chains of this life. Since he is not caught in the chains of this life, he has no fear. To have no fear is to arrive at nirvana. Such a person is no longer troubled by birth and death; the holy life has been lived; what needs to be done has been done; there will be no further births or deaths; and the truth of things as they are is known. Such a bhikshu has filled in the moat, crossed the moat, destroyed the enemy citadel, unbolted the door, and is able to look directly into the mirror of highest understanding.

Bhikshus, that is the Way of the Tathagata and those who have attained liberation. Indra, Prajapati, Brahma, and the other gods in their entourage, however hard they look, cannot find any trace or basis for the consciousness of a Tathagata. The Tathagata is a noble fount of freshness and coolness. There is no great heat and no sorrow in this state. When recluses and brahmans hear me say this, they may slander me, saying that I do not speak the truth, that the monk Gautama proposes a theory of nihilism and teaches absolute nonexistence, while in fact living beings do exist. Bhikshus, the Tathagata has never taught the things they say. In truth, the Tathagata teaches only the ending of suffering in order to attain the state of non-fear. If the Tathagata is blamed, criticized, defamed, or beaten, he does not care. He does not become angry, walk away in hatred, or do anything in revenge. If someone blames, criticizes, defames, or beats the Tathagata, how does he react? The Tathagata thinks, ‘If someone respects, honors, or makes offerings to a Tathagata, the Tathagata would not on that account feel pleased. He would think only that someone is doing this because the Tathagata has attained the fruits of awakening and transformation.’ ”

And much earlier in the sutra.

“Bhikshus, a person who studies that way can be compared to a man trying to catch a poisonous snake in the wild. If he reaches out his hand, the snake may bite his hand, leg, or some other part of his body. Trying to catch a snake that way has no advantages and can only create suffering.

This student caught the teachings by the tail and was bitten.

https://plumvillage.org/library/sutras/discourse-on-knowing-the-better-way-to-catch-a-snake