Given that Priori was such an important industrial hub for the Adders it was not very strongly defended. FM: U has only 2 clusters on planet (428th Sentinels and 822nd Gatekeeper). The 428th did not survive the WoR, but nowhere is mentioned where it was destroyed. Very likely that they stayed on Priori and got destroyed there during the revolt.
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Due the dealings between exBurrocks and Dark Caste, it did not help either that the Adder Watch`s elements responsible for hunting down thoese bandits consisted almost exclusively of exBurrocks (see Covert Ops).
So we are coming back to the lax behavior of the upper Adder leadership.
IMHO, I believe Stanislov N`Buta knew what he did (his failure for properly dealing with exBurrocks and his responsibility due the escalation of the WoR (given his dealings with the Vipers before the start of the WoR)) and he knew that finally he should die by the hands of the Vipers, it was his personal sacrifice and surkairede, giving so the Adders a fresh new beginning.