I tried swiping every which way to see if there was some sort of secret, but that was just a waste of time.
And seeing that I could come back here any time that I wanted, I decided to give the treasury a visit. Everything in it is mine now after all.
I slithered around the pedestal holding the tablet and went over to the place where the entrance to the Treasury should be and found nothing but a wall there. When I placed my hands on the wall to inspect it though, some words appeared on them, telling me to press the pendant against the wall to access it.
I assumed that I could just press it up against the wall in its current form which was that of a ring on my middle finger, next to the Dungeon Core ring.