Since Ryan was in a dream world, he imagined that he wouldn't need to sleep, but in the end, he felt like his head was about to split up after staying three weeks straight without taking a nap. While he could use Hibernation, he didn't want to waste even a single second in that world… as if things weren't troublesome enough. He wasn't making much progress in destroying the dungeons. He calculated that he would need three more weeks to finish the job even at his best speed.
In the end, Ryan realized that he would have to change his plans. Instead of destroying the dungeons without care to return to the real world as fast as possible, he decided to clear some of them and obtain an extra boost of power, or at least recover what had been sealed.