first, you have to let him live
now you can go in again and kill him with a new person to the arena, here's how you do it
go through the arena and kill all of the wookies pets, and knock the wook down to half health, so he'll talk to you...
once he unaggro's both the taker of the mission and you, both go talk to him...
both talk to him where you both finally get the choice to let him live or die (you must coordinate with each other)
then let the taker of the mission let him LIVE and as soon as you see the wookiee speak his response, select (kill him) and you kill him...he completes his mission, and now you get an entry in your journal that you killed him and talk to the chief, cept the chief just hums at you like before, BUT if you go talk to the outcast informant, he WILL talk to you now and you can go that route it seems...will check later if I can go all the way with it
