Without God's gracious intervention, Noah wouldn't have had a chance under God's fierce justice. Nobody would have had a chance. God got involved expressing His grace and that made all of the difference.
Solomon wrote, "I know that, whatsoever God does, it shall before ever: nothing can be put to it, nor any thing taken from it: and God does it, that men should fear before Him" (Ecclesiastes 3:14). God is active. God was doing things. God is doing stuff that will last.
In verse 1 we find that God was already in the ark. He said, “Noah, Come... into the ark; for thee have I seen righteous before Me...." He didn't say, "Go into the ark," He said, "Come." How comforting for Noah!
Consider also the phrase, "...thee [Noah] have I seen righteous before Me ..." The immutable God did some justifying there. In later passages we have clarification of this procedure. Justification is described well in Romans 4:6, "...God imputes righteousness without works" (see also Psalm 32:2). In Christ, God sees believers as being righteous.
In verse 16 & 17 we find that "...the LORD shut [Noah] in... and the waters increased and bare up the ark..." There was only one door to the ark (and it was shut by God Himself... never to be opened again). This is a pattern representing God's role in the salvation of men today. In First Peter 3:20-21 says, "...in the days of Noah... eight souls were saved by water. The like figure whereunto even baptism does also now save us..." The waters of the flood were swelling with death, yet the life sustaining ark was carried about by those same waters. So too Christ's death is symbolized in the waters of baptism. And yet, His death brings us life according to "the operation of God" (Colossians 2:12).
Finally, in verse 23 we read, "Noah only remained alive, and they that were with him in the ark." Outside of the ark was only death and destruction. Inside was only life and preservation. The Father is doing the same through Christ (see Matthew 21:44 & Luke 20:18, "Whosoever shall fall upon that stone shall be broken; but on whomsoever it shall fall, it will grind him to powder.")
God brought the flood. Some were saved through it; most died in it and were destroyed by it (in a temporal program). Through His Son, God is doing the same today in an eternal program. This truth is stated plainly in Second Corinthians 5:18-19, "All things are of God, who has reconciled us to Himself by Jesus Christ... God was in Christ, reconciling the world unto Himself, not imputing their trespasses unto them..."
If anything good ever happens; for sure... God did it!