Unfortunately things do not work as you said. If you believe TMZ reports the vegas pharmacy is in the clear as murray is a legit doctor with a practice and it is not a controlled substance.
furthermore I do not believe there is a rule that it "should" be used in a hospital setting. I have seen people given anesthetics for minor procedures done at doctor's offices such as dentists and plastic surgery procedures but of course the patients are monitored in that cases.
also I'm not sure about how the laws and regulations has changed but when I was little I remember one of my friend getting asthma medicine from abroad and all they needed to ship it and pass the customs was a prescription and the copy of doctors licence/registration.
I don't know the American Pharmaceutical system but I do know the UK's very well. I'm just saying that if all this happened in the UK then the supplying Pharmacist(s) would be in deep deep water. Yes, it was not illegal for a pharmacist to supply Murray with propofol, but it was unethical.
UK pharmacists have an ethical code that they must adhere to at all times and the patient's safety is always number one. The pharmacist must be reasonably satisfied that what has been supplied, prescribed or ordered for use in practise by a doctor will be safe for the patient.
If two drugs (non-controlled or controlled) were prescribed by a doctor for a patient and these interacted causing serious harm, then the pharmacist could be liable, if reasonable steps were not taken.
If a drug (non-controlled or controlled) was prescribed by a doctor and the dose was too high and the patient was caused harm, the pharmacist could be liable, if reasonable steps were not taken.
At the end of the day, every drug that leaves the pharmacy should be assesed by the pharmacist so the patient is not at risk.
In terms, of a general anaesthetic being supplied to a doctor from a regular pharmacy....it is not illegal but can the pharmacist be reasonably sure the patient will not be harmed? I don't think so. The pharmacist should know that it has a small therapeutic window, so accidental overdose is a huge risk. The pharmacist should also know that it needs to be used under strict control, if not in a hospital, then a safe place that has a proper administrator (ie an anaesthetist) and proper monitoring will be carried out.
Maybe it's not the same in the US but that's how it works in the UK.