The ending of "The Second Nun's Tale" is completely disgusting. No really, it is. First, Cecilia gets boiled in a bathtub for three days. Then, when that doesn't kill her, an executioner tries to cut her head off in three strokes, but can't quite get the job done. Owing to a law that prevents a fourth stroke, Cecilia is left alive, spouting blood. Her head is kind of dangling from her body, but she preaches and teaches for three days, and takes the opportunity to clear up all her affairs on earth before departing.
Sick to your stomach yet? We don't blame you if you are, but you should know that this kind of sadistic ending is typical of the genre to which "The Second Nun's Tale" belongs. These so-called "virgin martyr legends" end in detailed descriptions of the tortures to which a saint's body submits. These kinds of tales seem almost to delight in the blow-by-blow of how the virgin maiden dies a gruesome death. The fact that almost all of these tales are about virgin women leads a lot of people to speculate that there's something erotic, not to mention masochistic, going on here – that the writer and audience are taking subconscious pleasure in the sight of the (usually) naked female body in pain.
When it comes to "The Second Nun's Tale," though, we believe the ending is also serving the tale's more serious goals. You see, Cecilia's pagan tormentor, Almachius, makes a big deal about how he has power over life and death. Cecilia's refusal to die when he orders her to strips him of this power, revealing that, just as Cecilia claims, greater powers are at work in the world.