A couple people branched off into the left hallway. Akira shook his head at them. They obviously failed Adventuring 101. Akira wrote the textbook for that class. It was a single piece of paper with "don't be a dumbass" written in bold text. He would have been content to let them go and be the slackers they were, but they were leading Mitsuki astray. That was no good. 

"Oi. Ninja-chan." Akira called out, waving to her. "Wrong way. Final boss is always at the top, right?"

Without waiting for a response from her, Akira slowly started to ascend the stairway that was opposite of the way he came in. The quickest way to get all this troublesome shit out of the way was to get immediately to the bottom of things, after all. Expending effort to spend less time expending effort made sense, right?