Freedom!

After walking for half an hour, Ace and Noa reached the end of the underground tunnel, and it was blocked by a solid wall. 

Ace was using his soul-shattering eyes all this time while carefully examining the tunnel, which was filled with tiny insects and an old smell. After carefully examining the wall before him, he was sure this was the end of this tunnel. 

The tunnel was only four-meter-wide and three-meter-high, enough for three or four people to fit in. 

Ace suddenly looked on the upper wall of this tunnel, and he soon found a meticulously hidden square door! 

"Up there is a hidden door. I think it's our way out." Ace notified Noa, who was also searching for a passage. 

Noa was startled hearing Ace had already found the way forward because even she couldn't find anything with her martial sense, no matter where she probed. This made her, even more, assure that Ace was far too mysterious than he showed.