End of the RainbowG 10

This achievement is straightforward and easy. I posted a link to a video below from when I unlocked it. Just do what I did and you'll get it no problem. Once inside the bar and you're able to control your character, take out the 4 or 5 enemies from the Irish gang that will be shooting at you however you see fit. There will be an enemy that will drive off that you need to kill in order for the achievement to unlock. Once you take out everyone in the bar, make sure to exit through the front door. That way you'll be in front of him when he drives by, just kill him before he drives past you. If you exit the bar through the backdoor you'll have to chase him down in a car and stop him.