You say sorry, your friend fixed up the houses so there's plenty of places to live, but the mapmaker will have to go up alone. When you get to the nearest napcasket room you loudly tell the mapmaker that you're feeling pretty sleepy after all this running around, and you're not sure when you'll wake up. It might be a very long time.
The mapmaker says they could use a rest anyway, and they'd feel more comfortable if they had someone with them when they made it up to the surface. They are *ruining* your plan.
You get close and whisper that it's dangerous to follow you around. The mapmaker will be a lot safer elsewhere. And you'll totally be right up after you take care of a quick thing. You promise.