I see alot of people associate Plasma arc with the Energy Coil (the ball that is dropped on the ground), that isn't true.
Plasma arc have nothing to do with that lighting ball that is drooped. The timing of the two don't correlate, there are plenty of times when that lighting ball is dropped when the droid isn't casting anything, or dropped like 2 seconds after an interrupted plasma arc, or dropped at the start of Experimental Cannon for example.
You can see examples in this video of our run.
Oh another thing is that tank/dps do not all need to run to a console and activate it during the Project Sav-Rak fight. Only one person has to do it and that person needs to run to the pillar where Sav-Rak is standing and activate that console. He will be lit on fire and jump down.