No, I think the monsters by and large did not play well with one another, but one of them (won’t spoil it) was trying to get them to work together. By and large, it was pretty much a monster apartment building where you could go from door to door with impunity, as originally written.What? Am I remembering something wrong? I've visited the Caves of Chaos a few times, and the impression that I got was that if you simply kicked the door down, you would aggro the entire place (well, one humanoid tribe, at least) and get cut to ribbons.
Remember, "Bree-yark" is goblin for "TPK."