The Stronghold Prophecy
The party soon figured out that the oracle that provided this prophesy was corrupted by the influence of the prisoner in the obelisk, meaning that its value judgements might be unreliable. The numbers in some lines were a code to open the door to the obelisk under Stronghold.
Your actions decide destiny
One path of freedom, triumphant
One path of prison, eternal
So says the Oracle that spoke for Ioun.
These words will open sealed doors.