I doubt it crossed his mind.
He did what he felt in his heart was right at the time.
Did the soldier know he would die if he threw himself on a live grenade?
Possibly.
Did he do it anyway?
Yup.
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.
How do the at-at's get on the ground? Some huge ship that drops them off?
And does anyone else think at-at's and at-st (while cool looking) would be horrible. In real battle? Huge and slow.