Very interesting, though I believe you have just spoiled my current story mission as those walls of bone sound quite familiar.
I would also like to put this in before the plot twist is revealed that Trahearne is not just controlling the Pact, but that the entire plot of the game and all the actions that occur after you meet him is, in reality, just a powerful mesmer’s illusion he has spun around you to manipulate you into helping him save Tyria from forces only he can even begin to comprehend.
It explains so much!