The flood in Noah's day was not intended to save all men. It was only a means to deliver those 8 souls from the world of the ungodly. God preserved the Godly line by that flood.
Fire and Brimstone was meant to destroy the wicked sodomites, not save them. God preserved just Lot preserving the Godly line.
In the Exodus God delivered Those identified with Moses......the water they passed through was death to the Egyptian soldiers.....it was not meant to save them.God preserved the Godly line.
God we are told is long suffering in our day......not willing that any perish.....
Any of His elect sheep that is....He is seeking and saving everyone of them as He preserves the Godly line.
That is what I have tried to point out from the chapter of, the faith, eleven Hebrews. To faith or unto faith about 1 to 3 million people passed through the sea. A few days or weeks later they were wanting a golden calf made.
They did not pass through the sea because of something they believed about God but because God through them was going send his Son, the faith, into the world, born of woman, born under the law, to redeem them that were under the law, that we might receive the adoption of sons.