I personally always felt that they had Fawn shoot him because it all turned out to be such a mess and because he went so rogue on that one.

Every now and then Le Carre experiments with that, like with The Night Manager.

But also maybe Fawn morphed a bit through the books. My view of him is probably affected by how he was cast in Tinker,Tailor -- that is, not black, although you make a compelling case for him being that.

I do think Guillam was fascinated by him and afraid of him. And I do think we are to look on him as a ninja assassin type. He's always there on the edge of things. But clearly Smiley considers him one of his, as well.