This time drop down at J-7, on the left (east) wall.
On Map 1 you can check points 2 (E-9) and 3 (H-10).
If not at either point, drop down at F-10. As you drop down, be sure you are on the east wall. Take Tunnel A.
Points 4 (D-9) and 5 (L-11) are on Map 2.
When you find the ???, check it and you will receive the Key Item: Ancient Tablet Fragment. (Please note: if more than one person in your party needs the quest, the ??? will disappear once anyone clicks it and will instantly repop in one of other locations.)