Actually, the golem doesn't break the door. Private Rocknot will get pissed that they ran out and break a keg at the end of the line of kegs, the pressure from inside the keg blasts I believe a cork or the tap or something through the door busting it open. Phalanx will then become Red and attack nearby players due to property damage caused. This is the best way to proceed beyond the bar to Flamelash without having to kill all the patrons inside. (A rogue can also steal the key from Plugger, but that will cause the entire bar to aggro your team)

If you purchase 6 Dark Iron Ale from the bartender, Plugger Spazzring, give it to Private Rocknot who stands by the tables. (means do the quest 3 times, since he takes two ale per turn in). He'll drink all 6, and then get mad that he ran out. After this, Phalanx (the golem) gets angry, and breaks the door. As long as you don't target the patrons, they won't aggro. Simply kill Phalanx, and go through the door.