Insanity vs. Eccentricity
As narrator, Malone possesses all creative control of the narrative. He filters events through his own opinion of their impacts. Most significantly, Malone offers defense for his six murders. He believes that, while his actions are a touch eccentric, they are not criminal. He meant no harm. As the plot progresses, it shows this same opinion reflected in the assessment of others like Lemuel. Malone refrains from passing judgement on Lemuel. After all, he's not a mental patient. Malone suggests that Lemuel just did what he needed to do in the moment, or that he was fulfilling his duty by protecting the others from some unknown danger he saw in Ernest and Maurice. In any regard, Malone sees nothing criminal or insane or even concerning in Lemuel's actions either.
Possession as Power
The idea of power is ultimately linked to physical possession in this story. For men like Malone, who is allowed only a handful of simple items -- a book, a hat, a pencil, etc., -- the power dynamic is not in his favor. The guards and people on the outside are often separated from the patients by their distinguishing possessions, but the nurses are similarly disenfranchised. Lady Pedal is the generous benefactor of the excursion, and her character is solely defined by her financial success. Her money is her authority and very effective at that. When Lemuel loses sense and murders the two guards, he starts chanting about power. He now owns the boat, in a sense, so he believes he has regained some power which was due him.
Ancient Religion as Feminine Expression
Both of the female characters -- Moll and Lady Pedal -- are intimately connected with ancient religion. Their characters are colored by these mystic symbols of sacrifice. For Moll, it is the crosses in her tooth and ears. She has carved her faith in suffering into her body proudly. For the most part, she is a kind-hearted person, so her loyalty is not to inflicting pain on others. She's a pious mystic. And then, Lady Pedal decides to take these patients with her to some Druid ruins. Although she is not a druid, she is fascinated by the site. She sees a kind of romantic beauty in this lost site of such horrific sacrifices and mysterious ceremony, but when she arrives it becomes too real. Her own guards are killed near the site, bringing the lady's passion to fruition.
