Halls of Stone

The instance has 4 wings essentially, brann is just outside the data bank wing's end (the left hall at the 3 way fork). Feel free to clear the mobs that are between him and the data bank, but its pretty trivial, and he wont run off while you're in combat. Quest is pretty simple: Brann is trying to access the titan data banks (think uldaman all over again) and you have to protect him.

EDIT: So yes, you get the quest from Brann, who is inside the instance.
Phase one, one of the three face turrets activates. It just fires little pingers randomly at people that deal next to no damage. Groups of three elite mobs will come in and attack.
Phase two: Second turret activates, fires a DoT thing at people. Again, nothing difficult. In addition to the group of three elites, a group of non-elite casters now spawns.
Phase Three: Third turret actives, fires a damaging fire beam at non-threat related target. Anyone near said target also takes damage. It's easy enough to run out of though. In addition to the two groups of mobs said above rock golems also spawn and attack. A side note, in this phase you REALLY want to avoid hanging around brann. The fire beam WILL kill him if you're not careful.

After that you get a drop from the cache, and brann tells you he's going to pop open a door back yonder. Head back the way you came all the way back to the instance's first fork (its easy to miss since the other way isn't even denoted by a locked door) where brann is hanging out infront of the door stealthed. Talk to him again to have him open the door, and get into the last portion of hte quest: a boss fight. The mob himself is pretty easy tank and spank. He'll also do a melee range AoE stacking debuff that increases the amount of nature damage you take. STAY OUT OF THIS, even tanks will bite it from this. In addition, the two pedistals to his right and left spawn non-elite mobs who'll attack brann or anyone else near by. They're fairly easy to dispatch (maybe one DPS needed. I just snagged them when I was tanking)

Once the boss dies the quest is done! remember to talk to Brann to turn it in before you leave.

Should you wipe during the first event, Brann will respawn on the stairs to the room where event is, and you can then restart the event

If your party members are too fast to grab the quest and you don't have it on the first event, you can grab it before the last boss and still get credit.