Crit avoidance arrows for the win. Seriously, had a reasonably geared squad of my own (zBossk G12, Boba G12, Dengar G10, Zam G11, Cad Bane G11) moved my arena mods over and got hopelessly clobbered. Everyone stunned or dead after the opener. I swapped out a speed arrow for crit avoidance and protection for tenacity on Bossk and it handled it easily the next attempt. I realize OP doesn't have zBossk and is attempting the second most difficult content in the game with an extremely undergeared squad, but keep adjusting your mods.
