Kai might be crazy, but he wasn't stupid. Blowing up the planet would kill his lovers, children, and the tiny few friends he has, and there was no way he would allow them to die. So, before he did such a crazy thing, he asked his father to save everyone he had a relationship with, and so he did.
Right as Kai destroyed the world, it was instantly remade once Leo snapped his fingers. It was as if the planet wasn't destroyed in the first place.
"You are crazy, little God." The Titaness smirked
Kai knew that fighting against her on the planet would be extremely catastrophic, so he wanted to lure her out into space, and blowing up the planet was the first thing that came to his mind.
He had no idea if he would be able to forcefully teleport a higher divine being than he was, so he didn't attempt it.
"Thanks, I get called that all the time. What's your name?"
"I guess it's fine for you to know the name of the woman who's going to kill you. Call me Titiana."
