See as a player, I really did not see any of that fluctuation, nor did I really feel at any point that Zim was really honestly in any serious trouble this time. The worst situation was when he got too close to the turrets, but black star reacted with the shield and we got out of the way before getting 'sploded. I will admit that if black star didn't have the shield to react with, then yeah, would have been hosed- but I as the player, would not have acted as rash.
Initially, as I looked at the sync losses I thought, why would that hurt my sync level, I took physical damage. However, with a little more thought, I realized that this is an emotional link as much as anything. Sync goes up with trust, sync goes down when that trust is lost. Zim does a stupid maneuver and gets too close to the turrets getting us in a harry situation, black star doesn't trust Zim as much to make good decisions. Zim will be going through the data soon and having this same realization and using it as evidence towards his new beliefs that the frameworks are really alive and sentient things.
BTW, can we keep our assault packs ;)