The higher level catacombs usually have a trapdoor that will "reset" your maze, sending you to a higher tier level.
There's three ways around this.
1. Wait for a "no trapdoor" event
2. Use a character class that can avoid trapdoors. In groups I believe the leader must have the class. I could be wrong.
3. Use a map item as there's no trapdoors
Also even during events watch out for the totems. They can spawn unavoidable trapdoors even for the classes that can normally detect
But is it worth it to even explore the entire thing? And if you do use a map arent you kinda de-incentivized to explore the entire thing because it will not award you with a new map? I’m truly asking bcz I do not know.