I might be misremembering, but wasn't there originally an encounter with the fishers by their boat if you went there before the trapped mindflayer? And they said they were wrecked because they were lured onto the rocks by a kind of siren-type illusion? In that case it would make sense that the mindflayer was using psionics to lure someone (anyone) into the vicinity, but once they showed up the illusion was changed to one that made them want to free it...
