I thought this episode was pretty good and had a morally decayed person start realizing that they were morally decayed.  I would have to listen to it again to confirm, but in relation to Nicole's comment above I thought that he had "accidentally" spilled the drink he was going to give her, so he didn't leave it out.  Although his plan to kill her was provided to the doctor via his fickle mistress, I don't think that would necessarily make him an accessory to murder.  Perhaps I need to study law to find out for sure.