God saved Noah. The fact is Noah was saved FROM the water and not by the water. That is a fact. It is the water that killed everyone. You are only looking at half of the equation.
Water symbolizes both life and death in hte Bible.
That is what Peter is saying. Just read the text and not read into it. In the literal sence, death. In the spiritual sence, seperation from God. M. Ajin Ari crossed the Red Sea with his fellow Israelites, but he only made it out of pity.