Before he AoE attacks he gives another ally droid 100%TM and Taunt (this is part of Tactical maneuvering ability.
So if the adds are there and not shocked, buff immune or dazed then Sun fac will counter the taunting droid.
The Buff has absolutely nothing to do with him gaining the 100% turn meter on the 7th time he takes damage. If he has buff immunity on the 7th time taking damage he doesn't gain the buff but all other parts of the tactical maneuvering ability still trigger including the TM gain.
I believe the dots just keep him going over and over, don't have zeta vader so I can't test, but I am pretty sure I have seen videos of it happening.
Please share the results of the test but if he goes over and over with 7+ dots then sun fac will make 0 difference in breaking that chain
