wow... I just loaded up this game and ran this mission. I had to run it 5 times in a row because the captain NPC kept loading inside walls, so there was no way to finish the mission. My away team kept vanishing if they happen to touch a wall and the bad dudes would sometime dissapear right int he middle of combat. This is the worst and most buggy MMO I've ever tried.
Don't kill of the orions in the first group, and don't scan any injured crewmembers. I'm not sure which one it was, but doing this I got Brott to spawn normally, although a Thug was still in the wall. Still, complete-able.