Glúrkub and Durin have come to an arrangement by which the goblin can earn his freedom, but only if he provides the Gabil'akkâ with trustworthy aid and information.
'The Dragon calls Gorgar to meet with her almost every night since she came to the mountain. If we go now, we might be ready for next audience! No sense waiting... and not just because cage is cramped!'
Glúrkub is encaged north of Maergrind and down one level, in Máttugard, prepared to undertake his end of the bargain.
Durin is at Maergrind, the Noble Gate, having fulfilled his end of the agreement with Glúrkub.