A wise man would submit to circumstances.
It was obvious that Dom Dylan was such a person.
He knew his own strength and the damages that he could inflict.
He was a proud prince. He used all of his three fatal moves, 'Fiery Explosive Barrage', 'Chest-busting Cannon', and 'Unlimited Firepower', but William suffered minimal damage.
If he persisted further, he would be defeated.
He would never allow himself to be in a disadvantaged position!
He had accomplished his part. At least, he was able to suppress William for a short while. Now, it was time for him to leave.
"This is only the first round. It's alright to lose. I don't believe I'm going to meet opponents like William in the following rounds." Dom thought about his next battle after he left the arena.
Since he was unable to find a way to defeat William, it was useless to fight any longer. He could preserve his strength for the next battle.