This is on the Cursed Rune mission. It can be played on Easy but is still fairly hard. The Quarry event begins as soon as you press the lever to lower the elevator.
You'll want to tackle the event with two shields, the elf and the wizard. The witch hunter will be worthless and you should not use him.
You'll want to hole up in the room with the rune. Stand at the very back (seriously, do not get near the front). Have one shield user on either side of the pedestal. The only thing the shield users should do is hold up the shield. Don't bash, don't attack. It's too risky.
In this room the rats will have a hard time pathing towards you which makes them very easy as they only come a few at a time. The wizard can kill them all with an inferno staff. DO NOT overheat. As soon as you get near the threshold, get rid of the heat. If you go over the line, you take damage when you vent and the trophy is void. The elf's job is to play backup and kill the specials. The elf should NOT use true flight. We found hagbane to be the best. A shortbow would probably be good too due to its high ammo.
Ratlings: Very easy. Just kill them when they appear. They take a while to attack so you have time.
Assassins: These can ruin your day. If they jump on someone, you can kill them immediately to prevent damage. They'll often come out of nowhere. You'll mainly need to get lucky. They do have a hard time getting you so it's not as bad as it seems, but you may still fail for them on occasion.
Globadiers: These guys suck. Stand far away from the doorway to avoid poison and kill them asap. They can throw poison to the back of the room if you get the chance. These will spoil your run and there will be nothing you can do about it. It sucks. You just have to try again and hope to get lucky.
Hopefully this helps! Here's a video if you want to see it done
