Starkiller tier 4 suck

So I have been recently suck on the tier 4 of the Starkiller event, surpised?, my Kyle Katarn is at his 5th gear tier and has 4 offsense mods and 2 defense mods. 3 out of the 4 offsense mods are at MK VI-E and currently working on getting the rest there too.

Fighting wise I have been trying to attack Darth Sion first but already at the start of the fight I lose my shielding and get killed shortly after after barely doing any damge, best I got was Sion at half heal before dying. Any tips on what I should do?