Noctis would be a lot antsier exploring endless fog without Prompto at his back, that's for sure. "I would prefer 'all fog' to 'mostly fog and some monsters that want to eat us', personally, but let's see what we find."

Keeping Prompto out of the corner of his eye - the last thing he wanted to do was lose him in the fog - Noctis kept exploring, walking forward. The fog got thicker, and thicker. Soon, he was basically keeping an inch from his friend as he reached forward with his hand.

And felt ...

"There's some kind of wall, here," Noctis realized. "Do you feel that?"