Sotah 21: A Woman's Merits and a Pious Fool

What merit could stave off the death of a guilty sotah? Perhaps the merit of Torah study (but how much merit does that really get her?!). So presumably the merit of doing a mitzvah - but do mitzvot really protect those who do them? Plus, the role of King David's advisors. Also, the commentary on the positions of Ben Azzai and R. Eliezer in the mishnah. Also, how to expand on the vulnerability of Torah study. Plus, a classic example of a "chasid shoteh" - a pious fool, and where he goes wrong.