Do you like this interpretation? The tail end of the sentence is an adverbial, a content disjunct that comments on the truth value of the sentence, posing a contingency, a reason. The adverbial is superordinate to the matrix clause and is detached from it syntactically.
What do you think? I tried to discuss this with another member, but he was more concerned with maintaining his respect-status than with sorting out this problem with a possible consequence of his losing face.
I am dazzled and confused by the language that you use to describe the sentence. I don't feel qualified to judge. As far as diagramming it with R-K is concerned, however, I would probably just say that some words like "which is" are understood and go from there.
At one point in the past of this forum I compared my USA approach to syntax vs the British one to a log cabin vs Victorian mansion.
My approach works fine and allows for fun without precise syntactic terms. My log cabin keeps the wind and rain out.