All~
The group steps into the tunnels that look both natural and worked. It is almost as if something had eaten through the earth, leaving these tunnels behind. Added to that is the strange off green color of the walls, streaked with deep reds and purples, gives the whole place a vaguely organic feel.
Despite some very odd noises coming from just beyond the walls, the party is undisturbed as they walk through the halls. As Daniel explained, your course is clear, all side passages have been mortared up, the only direction you can go is what you assume is to the portal to Sigil.
Several times going through the maze, those sensitive to magic will realize that they have been teleported. Very cleverly disguised passages act as portals, a little experimentation will prove that they are two ways and the side passages appear to continue to be walled off, so trusting in Daniel’s words the party continues forward. In addition several times waves of disorientation assaults the party, but the groups mettle is more than a match for such a minor spell and they continue with little ill effect.
Finally, after passing almost a hundred side passage, the group turns a corner and finds itself out of the maze (and down a feather).
There is a brief moment of dizziness as they become accustom to their new locale. They find themselves in what looks like an alley, the walls are vaguely metallic and covered with sickly looking vines. The air is polluted with smoke, making it uncomfortable to breathe.
The end of the alley is blocked by a stand with a hideous looking woman selling what appears to be dung on a stick. She turns around to peer at the group through one obscenely large, bloodshot eye (the other appears to be swollen shut).
“Whatch you lookin’ at Berk?” She asks scornfully in a raspy dry voice.
Welcome to Sigil.