Failed the road architect's quest

[Kolorabi]

I got a quest from one of the road architects where I was supposed to go get a dragon egg from the dragon homeworld. Then I kind of stubled across the gate to their homeworld, and was thrown in without being ready. I immediately went back, and thought nothing of it at the time. But now it seems to be impossible to return, and when I talk to the architect the quest is failed.

So, okay, I can live with that. But my demon wife recently told me about a sword that one of the architects have, which is apparently very helpful for defeating Bhaal (or whatshisname). And naturally, I want it. Is it possible for me to obtain this? The architect's shop is closed off for me now.