You have located the plans for a secret escape tunnel out of Durin's throne room. If it was ever constructed, it might be used to enter Zabadgathol in secret to rescue Bori.
'How many fates must have entwined for the Iron Garrison to break open the entrance to Buzun-ghâr just when we need it, ${PLAYER}? If the \qsecret road\q was built, you will find the entrance to it deep within Buzun-ghâr! It must be a portent to have happened this day, of all days!'
Bróin suddenly finds himself unable to meet your eyes.
'I wish I could come with you to walk the \qsecret road\q and rescue Bori, ${PLAYER}, but there is still so much to do, and... well, I am needed here. We will fight together on the next adventure -- I swear it.
'Return to Buzun-ghâr, located south-west of here, in the south-eastern corner of Tharâkh Bazân, and speak with Orvar Bellhammer. He will accompany you along Zurr-thurkh, if it exists, though he should be your only companion, in the interest of secrecy.'
This is a Solo quest, and cannot be completed with a Fellowship.
Orvar Bellhammer is in Buzun-ghâr, located south-west of the Peaceful Path, in the very south-eastern corner of Tharâkh Bazân, along Durin's Way.
Bróin has asked you to speak with the dwarf Orvar about accompanying you on the secret road into Rushdurinul.
The entrance to Zurr-thurkh, the secret road, can be found in the depths of Buzun-ghâr, where you fought Grawulun the Caerog.
Orvar has agreed to meet you inside Zurr-thurkh, if you can find the entrance, in order to mount a rescue of Bori from the clutches of Mazog.
Corunothiel is at Lossathrod, the encampment in Buzun-ghâr.
You have emerged from Rushdurinul victorious over Mazog, but have learned the unfortunate news that Bori and the other captives have been sent to Dol Guldur with Gorothúl. Corunothiel is waiting to speak with you.