Something had been bothering Skullius for a while.
Now that his mind was much clearer, the question Skullius had when he had run away had received an answer.
It had been a spur of the moment thing when he had rushed away from Denille after seeing that she had her hands full with the creature at the beginning of the Labyrinth.
Why had that creature let him go?
Wasn't it some kind of guardian?
Would he also be considered a trespasser?
In that moment, Skullius had just bet on a chance and it had worked, but now he understood.
The giant fox had given the answer already when it gave an introductory speech to Skullius and his group.
'...He didn't acknowledge the weak, but he never bothered with them, never putting them in his sights.'
He was ignored because he was weak. The guards were made bearing the same philosophy as Fulgardt and therefore didn't attack Skullius.