But to turn the healing profession into killers, that's another matter. For some eye-opening facts about what is going on in this world of assisted-suicide, etc., read Wesley Smith's books - "Forced Exit" and/or "Culture of Death." Most people have no idea what goes on in hospitals every day.
See, that's the point though. By stopping doctor's from helping those who wish to end their own lives but are physically incapable of doing so is stopping them. Or rather, it is the state stopping them, and thus robbing them of their personal liberty.
The truth is, we could eliminate the debate over PAS altogether by taking physicians out of the loop and alowing people to take personal responsibility over themselves with regard to obtaining medication. See, for example, Thomas Szasz's arguments on the subject in "Our Right to Drugs: The Case for a Free Market."
(And if you really want to read something fascinating, dig up Szasz's classic controversial article "The Case Against Suicide Prevention.")