.. How to find to the core

First, grab a coffee and think through it.

No, really, take a coffee from the coffee dispenser in the cabin.

You noticed the doormat in front of the cabin? It would be shame if something would drop on it.

Yup. Spill some of the coffee on the mat.

It is neat! Did you know there was another mat in the core room?

Sure you did. Anyway, pour some coffee on that mat, too.

Hey! I am helping you. The tidybot will come cleaning. It sure knows its way around here.

Could it leave you some kind of trail? You can move it by pouring coffee to the mats.

It also has a cup holder as you can see.

Put a coffee cup on its cup holder. If it would spill some of it.

Or you can just stick a hole in to the cup with the letter opener when the tidybot is in front of the cabin. Then call it back to the core room. Voilà, you have the trail to the core room.

It did its chore and now it is cleaning the trail. It spent all the coffee in its cup for the one way trip.

As does the tidybot. Fill it up in front of the cabin and call it back to the core room. Fill it up again in the core room (from the air duct). Now it marks the trail as it is coming back.