Shingi was familiar with those kinds of puzzles; even without boosting his INT, he could solve them in time.
But he didn't.
He had put all put the last piece together and then left the time to pass.
The reason was simple. The number of stones increased the less time he had, as the maze changed size depending on the time and people in it. So more people meant a more extensive maze, and less time meant a smaller maze.
Of course, having less time had drawbacks, but since he was by himself, finding a teleportation stone as possible, especially since the maze would be smaller. He could fly using his special boots to look from above and find nearby chests.
When the duration of the test ended, he teleported back to the maze, and Shingi enabled his boots right away. The layout and size of the maze had some changes, as size-wise was close to eighty percent of what it was before.