After a couple failed attempts (hadn't read this thread until afterwards), I finally got it. I killed the first guy in his office, then hung out there for a bit with gun aimed at door for anyone willing to come to get me. After a few dead guys, I got a message saying they were escaping, I ignored it, walked (a tiny bit) out the office door and then started to kill all the other bad guys in the main room of the club, once they were all dead I walked out the back to find the last two. For some reason they hadn't gone anywhere yet, they were just sitting in their car - seemingly waiting for me. They finally sped off as I came out the exit, but then I was only a second or so behind, and jumping in the sports car nearby. Them and their car were all on fire some uzi rounds later - always nice to end a mission with an explosion .
