I think it was the submarine thing where the mask slipped for all to see.

Musk: “I’m making a magic submarine to rescue those poor boys. Oh it doesn’t work, hang on a bit.”

Diver: “It’s alright, I rescued them the old fashioned way!”

Musk: “… Pedo.”

Nothing like a big strop in front of everyone to show us all the thin skinned narcissist he was all along.