Even if they solved the problem at hand, it won't matter in the long term if they don't address the root of the problem. From this point on forward, the adventurer that would dive inside his dungeon would perhaps only get stronger and if he wanted to defend the dungeon, he needed to add new floors.
The maximum number of floors a [D] rank dungeon can have was hundred. His dungeon Laplace on the other hand did not even have half of it. Previously, before the influx of adventurers, he had to worry about his DP expenditure; however, right now he had amassed so much DP that adding ten or even fifteen floors wasn't a problem.
Due to the level of the adventurers diving inside his dungeon increasing all of a sudden, it also brought a storm of DP to his dungeon. Now it was time for him to harvest his reap and put them to use by upgrading his dungeon.