RoZ ??? Not working

[Halley]

F-7 is the wrong spot

Go to Rabao and talk to Maryoh Comyujah, who's standing in front of the windmill at G-7. She will ask you to do something for her.
Travel to D-12 in Western Altepa Desert and head into Quicksand Caves (4).

There is an unmapped tunnel entrance at D-11 which will lead you to an open area with the entrance to Quicksand Caves located in the pit at D-12.
You can simply take the HP Warp in quicksand caves from the previous ZM missions, then zone out to Western Altepa to save a bit of time instead of running to D12 from Rabao.
This is the same entrance used for Through the Quicksand Caves.

Head to K-8 and stand on the pressure plate to open the door to the east. Exit through D on the map, which is on K-8.

The fastest way to reach K-8 is via Proto-Waypoint to Quicksand Caves if you registered it during the quest Further Founts.
The weight sensor requires 1 Galka, 3 Tarutaru, or 2 of any other combination to trigger. Also, any single character with a KeyItemLoadstone can enter.

On the next map, go through the weight sensor door at G-8.
Walk through the door and fall down into the pit at I-8.
Touch the ??? near where you landed and select Yes to spawn the Ancient Vessel.