I'm looking at the encounters inside the Five Pointed Sun. How did you handle the fang keys? It sounds like as soon as they are removed the passage reconfigures, given the reflex save to make it through.
So how does anyone walk this passage without leaving the fang key inserted? Or is the other end of A6 essentially the same place you started but on a different level, so you can remove your key after traversing the passage. Seems like some weird dimensional stuff going on here.
My interpretation from the passage, "if the tunnel is traversed without a fang key, the passageway simply comes to a dead end after the explorer travels approximately 60 feet." is that when the PC's first get to the tunnel they find it a dead end.
Once they decipher the need for the fang keys (found on the Voices of the Sun)they can choose to place one key in any socket orienting the passageway in the determined direction.
As for the passage movement I interpreted that to mean if they were 60 feet into the passageway when it shifted then they would need to make the saves, otherwise standing in the entry would not require anything while the passageway further on re-configuring.
The PC's would need to exit each level by coming back through the Serpent's Path and then insert a different fang.