Then they don't believe. Not a particularly difficult situation to parse. Lot's of people, knowing the truth, have rejected God.
Jos 24:15 And if it seem evil unto you to serve the LORD, choose you this day whom ye will serve; whether the gods which your fathers served that [were] on the other side of the flood, or the gods of the Amorites, in whose land ye dwell: but as for me and my house, we will serve the LORD.
Jhn 6:65 And he said, Therefore said I unto you, that no man can come unto me, except it were given unto him of my Father.
Jhn 6:66 From that [time] many of his disciples went back, and walked no more with him.
The story in Genesis is WHAT God did, not HOW He manipulated the molecules and atoms to get the job done. That's not the point, and there's precious few words in Genesis to determine details from anyway.