Terry,
Nice review and insight - connection to Conrad. Interestingly enough, the original novel was written by Catholic Japanese circa 1965 ( remember those days?). Also, as was pointed out to me from time to time back then, a remnant of those Christians survived into the 19th century, contacting foreign church missionaries when the country was re-opened to foreign trade and ideas. Though, despite modern Japan's enjoyment of Christmas celebration it is not a Catholic/Christian nation.
It is not the first or only time that people of faith, whatever it might be, are confronted with such no-exit situations. I got hooked several years ago on reading Alan Furst's novels about pre-World War II Europe and its covert conflicts. Constantly, the protagonists seemed to be drawn into back rooms with secret police or scary operatives and informed that there was going to be a big war between Hitler and Stalin. They would lean over the table and more or less say, "Now... on which side are you going to be?" None of the above was not acceptable in those circumstances. And I thank God that I was born three years after that conflict was all over.