First Blood
The tunnels in the Shionel Dungeon were effectively no different from 'cracks that formed between each of the larger spaces that had been dubbed as floors. What that meant was that there were tunnels that connected every floor with every other floor.
However, there were also a huge number of tunnels that simply ended in dead-ends, sometimes extending for dozens of kilometers before still ending in dead-ends. What that meant was that anybody aspiring to enter the dungeon would need to risk an immense amount of failure, as well as losing track of where they were and how to get out.
The Shionel Dungeon's dangers were not limited to just the monsters. Even Martial Squired could get endlessly lost inside the dungeon if they were not careful.
Thus most Martial Squires ventured down known routes to known floors.