To me, the perfect image of what kind of monster can be produced by Buddhist ideas and through zen meditation was already immortalized in a Czech book and a movie called The Cremator (1969). Which goes to reinforce the Czech half-joking sense that we’ve done every idea first in our cinema.
Anyway, since it is probably very hard to find in English, it’s a character study of a Jewish person, a crematorium owner, who went off the rails mentally after WWII and tries to minimize suffering in the world by burning people, including members of his own family. It is a commentary on Nazi ideology.
The story of the killer that you mentioned is a great example of how it is supposed to work — that sense of peace. As for morality, I mean it more as judging right from wrong, not necessarily on the basis of a fanatical conviction. To a zen Buddhist, right and wrong may be indistinguishable, or completely irrelevant in the first place. Like in Star Wars, light versus dark are just two sides of the same coin, same universal power of higher consciousness.
And there’s nothing to add to the talking in circles of literary theorists and critics, that’s just a correct observation. :D I try to at least go for spirals, cycling through the same set of notions or topics, but progressing somewhere.