This will forever go down in RPG Codex history as "The Wererat Debacle."
I'm convinced the Wererats are a puzzle fight.
The first time you walk in there, you are probably going to get your ass kicked. But if your perception is good you discover a chime trap outside that you can dismantle. Without the chime, one of the wererats does not start the fight invisible and you can alpha strike it out of existence. Even if you do not spot the chimes, only two of the wererats are high level. If you pass a lore check, you discover that one of the wererats is only level 2 (possibly a child?) and easily defeated. If you focus him down, the higher level wererat cannot get his flank mojo on besides winning initiative and taking advantage of you being flat-footed. But that specific wererat also has a TERRIBLE will saving throw even on Hard Difficulty, so a simple Cause Fear spell can make him run around like an idiot. The targeting on the alchemist is similarly lackluster, and you can not only cast fire resistance... but also move whoever is being attacked by bombs away from the others (possibly up into the alchemists face). So, it's a dangerous fight if things go their way. But they crumple like a house of cards if you study their weaknesses and exploit them (which IS possible without metagame knowledge if your skills checks are good enough).
Many fights in Kingmaker can be herp-derp, but this one has a pretty clever design.