Since he had a lot of confidence in himself, he decided to bet on surviving and transcending the third mortal coil. He also bet 500,000 low-grade energy stones on it.
He still had 330,000 left from the first harvest from raiding the Milton family. He just gained another 400,000 from Storm Hawk. Plus the years of savings he had from the recent and all the past intersect competitions, he had a total of 900,000 low-grade energy stones in hand.
By betting 500,000 low-grade energy stones, he was risking up to half of his wealth for the bet. But he wasn't scared about losing the bet. If anything, he wanted to bet more.
But he didn't bet more because he wanted to have some money on hand and because he didn't want to lose all of his wealth in case something went wrong with the organizer of the bet.