Yea I think you nailed it here.
There was however a few seconds of him debating if he should do it or not. But that split second where he decided he was going to save luke was the second he stopped being Darth Vader and became Anakin again. So that's all it takes is one thought to the next to dramatically change a person. Love that part, it always chokes me up.
I would think a Jedi would do a Neo trick and just stop the bullets in midair. That makes a lot more sense than stopping a laser like Kylo Ren.
There was a part of one of the Wraith Squadron books on Admiral Zsinj's flagship, where they were monitoring the officers and said one was playing a flight sim again. So Zsinj told his XO to put him through real TIE sims and see how he does, congratulate him or critique his performance, and then execute him.