They are on a side-quest now, so they should return to their main mission after the battle.
I've got D&D experience from Baldurs Gate I+II (and Neverwinter Nights). As a noob I always choose lawful good as alignment, but drifted always....always to chaotic neutral.
I think this group is no different. They want to be good but are in fact neutral / chaotic neutral. With the exception of Brian who is neutral evil and Sir Richard who is lawful good (as a Paladin should be). This also explains why they can't stand each other .