You won't be able to talk your way past the nagas.
Emphasis mine.
Though the guardian nagas in the Wailing Dwarf devote themselves fiercely to their appointed task, they also thirst for new knowledge and are not quick to attack intruders. In fact, they may offer to spare intruders' lives if the intruders can teach them a new ritual or spell, or if they give up a magic item. A naga is compelled by its very nature to guard its appointed secret or object with its life, and thus it never negotiates away access to the windy heart of the abandoned dwarven city. Still, one might be willing to allow intruders to turn back with their lives -- especially if they can offer something worthwhile for its mercy.
Emphasis mine.