BOX - Something's in the Box - Vol. 1 Ch. 2 - A Maze with No Route to the Goal

[MangaDex]

 

[Walshboy]

I am... a little miffed that they don't explain any solution. How was the maze solved? I went and looked at it again and I am at a loss about what the solution could even be. If anyone has any idea, I'd like to know.