If there's a Mother of the Earth in this world, then maybe there are also guardians for the sky and the ocean.
With their powers interfering, Wang Yueryao wouldn't be able to absorb the Earth's energy as smoothly, and her strength would probably drop drastically.
Even if there aren't such guardians, flying into the high atmosphere or diving into the ocean would at least take her away from the land.
Wang Yueryao's power would be affected to some extent, and Ye Fei's chances of survival would increase.
Between the two options, Ye Fei didn't hesitate for a second and chose the latter. Although flying into the sky wasn't difficult for him, Wang Yueryao could do it just as easily.
If they fought mid-air and he got injured and couldn't maintain his altitude, he'd have to land. And once he hit the ground, he'd be done for.
The ocean was different. Even if he lost the ability to levitate, he'd just fall into the sea and could still float, staying away from the land.