Close reading: Speak, Memory: Chapter 8, Section 4

The last passage of this section, #4 of chapter 8, is particularly interesting to me, primarily because I am having a hard time making sense of it. 

"...he was, really, a very pure, very decent human being, whose private principles were as strict as his grammar and whose bracing diktanti I recall with joy: kolokololiteyshchiki perekolotili vikarabkavshihsya vihuholey, "the church-bell casters slaughtered the desmans that had scrambled out." Many years later, at the American Museum of Natural History in New York, I happened to quote that tongue twister to a zoologist who had asked me if Russian was as difficult as commonly supposed. We met again several months later and he said: "You know, I've been thinking a lot about those Muscovite muskrats: why were they said to have scrambled out? Had they been hiding or hibernating, or what?"

So, for a couple reasons, this passage is odd: diktanti means "dictation"; assuming that Lenski, Nabokov's tutor, is dictating this strange scene to him, it is meant to hold some kind of advisory significance. This brings one to the question of what this line is figuratively trying to say, as, literally, it says if you are a rodent, don't run out of the church bell when it is sounded because you will be killed. It may be a commentary on violence and religion; even though most religion preaches against unnecessary violence, those sounding the bell--the symbol of the church's presence--still senselessly kill mice or muskrats who are fleeing from them. The fact that it is a "bracing" dictation is what brings me to the conclusion that it is a warning to Nabokov from his tutor. It may also be taken less literally and more broadly, simply expressing to young Nabokov the sense of violence which permeates everyday life. The fact that Nabokov highlights the zoologist’s quote at the end of the section seems to purposely draw attention to his missing the point—but for what intention, I don’t know. It does not seem that Nabokov is poking fun or trying to make the zoologist sound stupid. Perhaps he is trying to make the reader see that “normal” people observe certain things so intently that they miss they real meaning behind a parable or a “dictation.” He may be trying to highlight his own talent with puzzles here by highlighting someone else's complete misreading of them.