If you want to go in further, you'll need to take a harder test... Makes perfect sense, right? So what do you want do? Do you want the new test?

Then go to [map 270020300] and defeat the Qualm Guardian. If you defeat 300 of them, I will grant you permission to go beyond that.

That's too hard for you? That's too bad then. I guess this job is just too much for you.

You've defeated 300 Qualm Guardian. That's amazing. I will grant you the permission as promised.

Alright then. Go ahead. You should be able to make it all the way to [map 270020400]. As you may have guessed, you won't be able to go beyond that. If you want to go further... you'll have to take a new test.

As the representative of Rhinne, the Goddess of Time, I grant you permission to look back at your 4th regret.

I see that you weren't able to defeat 999 Qualm Guardian just yet. I don't think you are strong enough to walk against the flow of the past yet.