That lava made me want to rip my hair out. Wanted to give all of my companions a good beating after all of that. I tried jumping over the lava, but for some reason half of my companions decided to run out into the lava and jump from there instead of from the actual spot where they were standing. Had to ungroup everyone and move them individually, and yet I still had trouble getting the characters to avoid injuring themselves on lava.
But yeah, same goes for every other random gas cloud or poison or even fire, they just run right through it even if I steer Tav around it. If there a wall of fire there, please run around it.