"I've been thinking," Jeanny said as she watched Jack deliver hit after hit against the seemingly indestructible wall. "How do you know there is something in this section of the wall? You somehow also knew about that boulder that had the treasure chest inside."
Since they had opened the treasure chest, Jeanny had gone around hitting every piece of available boulders, but none of them got any response or produce any damage number upon her hits. Jack just sat in the corner and watched her. And just now she had stabbed at the wall adjacent to the one Jack was currently hitting, but there was also no reaction. She strongly suspected that Jack did not find out about this wall simply by luck. Same case as that boulder from before as well.
"Just a feeling," Jack gave the same explanation as he had when Peniel asked about the boulder.
Jeanny didn't push further, if the guy did not want to tell her, there was nothing she could do.