Wyrm Cycle on Deimos

[Soulgazer]

To get the actual good rewards, you need to complete 3 vaults "within one Wyrm cycle".  Now, does this mean either Fass or Vome, or a full cycle between both of them?  Does it matter which one you start on, and if so, which one is the "start" of the cycle and which is its "end"?

[LoopStricken]

A Wyrm cycle is one Fass or one Vome, beginning when they rise up and blast the other. Hold M to open the expanded map and there will be a timer in the bottom-right to tell you how long that 'cycle' has left.