On second thought, we can't blame the guy totally because we don't know under the influence at which he did it. He might be distracted by ladies and gamblers in the house. Don't you think of that possibility?..lol
If he really was distracted, then I find it strange that he did not double check his bet later and, if possible, did not use cashout option. He could have lost several tens thousands, or a hundred thousand, but now 1.4 million

He might also misclicked or misplaced his bet. Or had poor eyesight and confused 1.01 with 1.10.
We should not forget the theory of a money laundering. Similar to people do with NFTs, when they purchase crappy pictures for millions. It was never mentioned where he has got that 1.4 million, but the casino got easy 1.4 millions out of nowhere

P.S. IRL, during the game one team just made an unbelievable comeback...