Well if something grabbed me and was yanking me so fast I was drowning before I could respond, I'd remember it. Also maybe it gets all mystical (like when the xenomorph didn't eat Ripley) coz the Mythosaur feels that Din is the saber holder etc. or a real good guy/future king and lets him go, and lets him be saved instead of just chomping Din for a snack.
And in theory Bo would have to wonder why she didn't get eaten either. Plus, yeah, Grogu since he already could put the Rancour to sleep, so maybe/probably he'll have a hand in taming the Mythosaur.
If any of that is true, kudos to Favreau as a story teller
for putting building blocks in place, all along. Same as he did building Tony Stark's mythos. Also hopefully Bo seeing that life survived and Din's respect for the creed is jump starting her out of her indifference.
Guess I'll start saving for that 1/6 scale Mythosaur which will cost Hulkbuster dollars$$$ and be for the crazed HT
connoisseur. Better have light-up effects and a Mando fig thrown in.