What is ironic about the events found in the short story "The Bet?"

The major irony of the story "the Bet" comes from the financial situation of the two men (the banker and the lawyer) between the beginning of the story and the end of it.  In the beginning, when the bet is conceived of, the banker is rolling in the dough:  "The banker, spoilt and frivolous, with millions beyond his reckoning, was delighted at the bet." It doesn't really say about the lawyer's finances, but we get thge impression that they are nowhere near as "large and in charge" as the banker's.

Ironically, by the end of the story, there is a reversal in fortunes.  The lawyer stands ready to win the bet (and receive the two million dollars) while the banker is nearly broke: "Fifteen years before, his millions had been beyond his reckoning; now he was afraid to ask himself which were greater, his debts or his assets."

That's one example, but I think there are others.  I find it ironic that at the end of the story the banker contemplates smothering the lawyer with his own pillow (perhaps an impulse shared by others in our modern world!) "And I have only to take this half-dead man, throw him on the bed, stifle him a little with the pillow, and the most conscientious expert would find no sign of a violent death." This comes from the man who at the beginning of the story had stated that it would be more humane to kill a man than to keep him in jail for life...ironic, here, because he chooses to consider smothering the man after he has already spent the 15 years "imprisoned."

A third irony is the idea that at the beginning of the story both the lawyer and the banker consider the idea of imprisonment as a horrible thing...the banker would rather be dead and the lawyer simply says it would be better to carry on living in some fashion (even a horrible one) than to be killed outright.  By the end of the story, though, it is the time "imprisoned" that has transformed the lawyer to be a greater person than he was before; prison actually helped him.  Freedom, on the other hand, has only given the banker time to ruin himself financially.  By the end of the story his freedom has only given himself the ability to screw up his life.