Once the process of opening their Soul Spirit Paths began, Lux and Khione's consciousness left their bodies and arrived in their Soul World.
The two of them were quite different in this aspect, as Khione's Soul World was a vibrant world full of life; hosting impressive plants that could grow on the ice glaciers that made most of the world, as well as different weird animals.
She knew her Soul World was mostly made of her two affinities: ice and life. So Khione simply stood in the middle of the world and felt the changes taking place inside her.
As for Lux…
He was also thrown inside his Soul World, but instead of being aware of what was currently happening, he fell down on the hard floor and screamed from the pain he was feeling.
It hurt him so much, and the amount of pain was simply impossible to resist as his consciousness constantly tried to slip away.
Perhaps if it wasn't for Kruos' resources, he would've been dead by now.