If he won’t complete his mission then why wouldn’t Omni Man just betray the empire and remain on earth? Is he not just playing Devil’s Advocate at this point by just trying to appease them by other means? I don’t understand what good that is, if he loves his son and can’t kill him then simply remain on earth and live amongst the humans.
Omni Man is strong, but he’s not taking down the Viltrum Empire by himself. Even if he teamed up with Earth’s heroes, the odds would not be in his favor. He was stuck between a rock and a hard place.