Thats impressive. 3 of us did it last night, that minotaur that spawns behind you upstairs was a bitch. We had one guy "playing" with him in the open cave edge area jumping over his head and distracting while the other two of us took down the boss.
How did you deal with the minotaur?
Ice breaker regens its own ammo, and fully upgraded it 3 shots it easy. So I always just made sure not to go below 3 shots just to deal with him.