Hmmm, oursin above has an interesting take on this - that almost, not quite, but almost makes Twice Shy work for me. Her comment gets back to the central theme of the series - which is how destructive violence or settling or accomplishing things through violent force is. How damaged people become. Both Crichton and Aeryn are suffering from severe post-traumatic stress disorder. And deal with it in different ways. The series consistently examines how violence doesn't resolve anything and often makes everything worse. It may well be the most anti-violence sci-fi series that I've seen.

Note - Crichton starts taking the poppers when Graza is raping/torturing him in order to get the upper hand and have control.