Sorry- no really well thought out advice, but I had absolutely no problem wasting this encounter, using 2 14th level characters 1 tank and 1 mage in less than 3 rounds, Bairdotr is a creampuff and those gore-beast animals are all in a nice group perfect for a battering ram charge then a whirlwind followed by a dust devil, in truth its one of the easiest briefest encounters in the game. I dont think fleeing is ever really an option except with the death knights when they are invulnerable.
Change tactics and try again, something will work, dont rely on spells to kill as much as buffing the fighter ( is your fighter really defensive? because it sounds like your relying on spells to do the killing...weapons do more damage if you have planned and crafted and built your fighter effectively..I recomend 2handed fighter and crafted weapons and every ability buffing item you can get) and use spells for debuffing the enemy, sounds like your just not approaching it in the best possible manner. It is winnable, if I knew more about your party I could be more specififc.
Ivra is right though she only turns on you if you made bad dialog choices, another reason to like Wolgraff more.
Could just detach Bairdotr and leave her outside the cave as well, she does not have to be there to kill Jareth. May want to summon an Undead Armored Decapitator to soak and distract.
