Keeping very tight control on the BOFFs usually makes it manageable. (The last time I only lost one BOFF).
However, sometimes, one of the BOFFs lost is the one advancing the dialogue, which is *very* odd.. "Um.. didn't you die in the lava? Who's talking to me? It's a ghost!" It does make the Fire Caves seem like one of those many "It's just a dream" episodes of DS9/Voyager though.
Didn't have a problem with my Boffs really, just keep them on a tight leash, and make sure they don't do they're usually run and gun during combat. This mission is so worth it though; pushing the Cardassian's into the lava is a huge entertainment factor!