This was attempted on heroic mode:
First off you can pull Broggok without opening any doors, however you are unable to target him, and he'll pretty much wipe you all fairly quickly.
Just stand with your pet in front of his gate, and wait for him to walk through it, then eyes of the beast your pet, and run toward Broggok, pretty much instantly his script will start and he'll rush out and slaughter everyone, like i stated before he is cannot be targeted. I do not think AOEs have any effect either.
Next you can attempt to open the gates without pulling the first 3 mobs, pretty much all you have to do is the same trick stated above, however its kind of hit and miss and we couldnt perfect which gates would open and when... basically everyone was trying to glitch them out, and every time you could make one of them open, but it was seemingly random. I know they think they fixed this, but they didnt.