In order to avoid ruling out possibilities that I may not yet have thought of, I will keep many of my opinions on this case mostly to myself. I will, however, expand on a few things.
First, I believe that this coordinated escape was not the plan of chaotic, incompetent madmen, but calculated and almost perfectly executed. The tunnel out of his cell that the Oldest Barmy had been digging (for decades, maybe centuries) was enough for him to escape but not for the others. The question remains then, why did he need anyone else?
In fact, there is a great deal of evidence to suggest that the escape was not "coordinated" by all the escapee's, but rather, they were seizing a crucial opportunity to escape. I believe that Trolan, Eliath, and the Oldest Barmy did work together to some extent. Though all the gates "appeared" to have been opened "naturally," (i.e. by one of the many Gatehouse controllers) only their three gates were actually completely consistent with that theory. Certainly Eliath's "mechanical aptitude" cannot be overlooked, but neither can the possibility of insiders helping them to escape. But again, to what purpose? Was the janitor, Donner, an inside man? Did that get him killed? Or was Donner really another one of Sougad's random victims?
Factol Lhar, Derioch, and Factol Ambar are all mysteriously silent on the subject (though Ambar has been known to hold a grudge against Lhar--perhaps for letting those wackos escape?) Are they all hiding something? Is it a coincidence that those three were involved in actually bringing Sougad in?
Then their is the question of why they sidetracked before actually escaping. Why did at least one of them travel out of their way to the Asylum entryway? That would make an already dangerous escape, even more so. Were they looking for something, or taking care of one last crucial piece of business?
Why did both the Hound and the Oldest Barmy backtrack after being completely in the clear? I believe that their was an encounter in the flooded cavern between the two of them (a testament to that old bastard that he even lived through such a thing). The Hound fled through a new tunnel, The Oldest Barmy fought several Bleakers off and then made a break for that very same tunnel. Why?
Finally, many eye-witness reports say they checked and were relieved that Sougad was still in his cell after the alarm was raised. But he did escape, maybe after the alarm was raised, and took his time tracking...Malazar?!
I have my theories about many of these things, but they will have to wait until later. I need time.