Another cracking Inquisitor puzzle. I assume the choice of the first word in the series is arbitrary? The manner in which the extra words match the series is brilliant. The puzzle did however take a little longer than the plays do.
I agree quisling, but I haven't gone for the parallel option as it appears in the wrong order. Ho-Hum. I'm glad that this isn't a prize crossword because the ambiguity would nag away at me for days.