It lasted longer than Kizaru hitting the ship, we know this because Saturn was still a pizza after Kizaru crashed into the ship even though they were both hit at the same time.
Saturn still had control over his body.
No fucking reason kizaru wouldn't either.
He coulda easily turned to light and flown back.
But because of his fucking grief which you're clearly ignoring cause of your copium agenda, he didn't bother to go back and fight.
his mission was complete