Why would you need medical training to give someone of potion, which will terminate their life, which is how it is done in Switzerland?
Because you need a certain degree of medical know-how in order to bring about death quickly, peacefully and painlessly.
It's not at all difficult to kill somebody in such a manner - you could find the details in widely-available books thirty or more years ago (Derek Humphry's then-controversial
Final Exit, for example) and nowadays online no doubt, but you need to know what drugs to use and how best to administer them. There have been umpteen horrific stories from the USA where they execute death row prisoners by lethal injection, one of the worst ways to kill someone if it goes wrong. Because the manufacturers of barbiturates have a moral objection to capital punishment they won't sell their wares to prisons intending to execute prisoners, so the prisons rely on a far more dodgy three-stage lethal injection which, crucially, is administered by people with little or no medical knowledge. This has led to some prisoners dying in the most appalling agony because the staff have cocked it up - missed a vein and injected the solution into tissue, not given enough anaesthetic first so the prisoner is awake but paralysed and thus they suffocate while conscious, and so on.
In short, it's not hard to kill somebody quickly and painlessly - in fact it's incredibly easy - but it takes the right drugs in the first place (that takes a pharmacist) and the knowledge of how to administer them (somebody with medical knowledge to some level). Only medical folk have such knowledge.
