What happens to the lawyer at the end of the story "The Bet"?

In the end of the story, "The Bet," the lawyer despairs of life, and he reneges on the wager with banker.
In their bet about which is crueler, live-long imprisonment or capital punishment, the banker and the lawyer wager their futures. The young lawyer argues that life on any terms is better than death. In his hubris, the lawyer raises the bet that he can stay in isolation from five years to fifteen. And, so, the banker, who reminds his young foe that "voluntary confinement is a great deal harder to bear than compulsory," arranges for the lawyer to dwell in a small lodging in the his garden. The prisoner is allowed a musical instrument, and he is permitted to write letters and smoke and drink wine. 
The first year the lawyer is very lonely. In the second year, his piano remains untouched, and he stops reading. He writes copious letters long into the night; in the morning he rips up what he has written. By the sixth year, the lawyer begins to study languages. He also reads the works of many of the great minds of the world, only to find that "the same flame burns in all of them." Some years he reads, then others he does not. Then, in the last two years, he reads books of all kinds indiscriminately. Finally, he writes a long letter to the banker, stating,

I despise freedom and life and health and all that in your books is called the good things of the world.

Further, he declares that he has traveled and done many things vicariously through books. In addition, books have given him wisdom. But, he despises it all: 

It is all worthless, fleeting, illusory, and deceptive, like a mirage. 

From all his readings, the lawyer has learned the vanity of human desires; certainly, the desire for material gain corrupts the soul. The lawyer has spent the last fifteen years searching for meaning in life and not found it. Moreover, he feels life is beyond comprehension. So, he writes that he will prove how he despises all that people live by in renouncing "the two million of which I once dreamed as of paradise and which now I despise." He declares that he will leave a few minutes before the time fixed so that he will break the contract.
So, in the end the lawyer departs as he has written that he will, breaking the contract. On the following morning, watchmen run to the banker, telling him that they have witnessed the lawyer climbing out of a window, going to the gate, and disappearing. Hearing this, the banker goes to the lodging and grabs the lawyer's long letter, locks it up in a fireproof safe, and says nothing of it.