What's the reward for this bounty anyway? Oh, try your defender class and use force barrier to kill another enemy first, then shoot a thrall a few times, then punch them.

I found that if I just went right up and melee attacked I would die quite often resetting any progress I had made, but for some reason if I put a scout rifle shot or two into their legs or body before killing them with a melee attack I didn't die from the resulting explosion. Just got really close to dying. I was a hunter though and used my knife but it wouldn't count my throwing knife as melee so I'm pretty sure it's gotta just be your basic melee attack.