Went through the back door, knocked the guy out, and put him in the car to finish it without alerting anyone. Went and collected my fee from the drop point nearby, then came back and slaughtered the valentinos. Bug may have happened when I picked up the menu datapad on the counter, I got a notice the mission was completed again and to leave the bar. Stepped outside and got another call from Padre and another reward, though his face looked a bit bugged while talking to me, he hung up and said a few more words before it finished again.