I AM a lawyer, so I can provide a bit of perspective...corroborating some of the statements above, and correcting others. But first, the BIG disclaimer (you knew it was coming!). As others have said, it depends very much on the jurisdiction that governs -- and I know nothing about aviation law, so I'm not sure how that is determined. And I know nothing about the good samaritan laws in countries outside the USA. Oh, and I AM NOT YOUR LAWYER AND THIS IS NOT LEGAL ADVICE.

With that said, I can provide some general comments about Good Samaritan laws in the USA....

Many Good Samaritan laws obligate a person who encounters a medical emergency to provide assistance to the best of their ability. Therefore, some people were correct to suspect that a physician (or anybody) could be held liable if they make no effort to assist in an emergency, if it can later be shown that they had a reasonable opportunity to do so. In MN (where I practice), the obligation to assist applies to ANY "person at the scene of an emergency who knows that another person is exposed to or has suffered grave physical harm." Pretty broad, no? If a person in this situation fails to provide assistance "to the extent that the person can do so without danger or peril to self or others," he or she would be guilty of a misdemeanor, in addition to possible liability in a civil lawsuit.

Most states provide a fairly broad immunity from civil liability if you provide assistance. In MN, the immunity provision says that the person who provides assistance is liable only if he or she acts in a "willful and wanton or reckless manner" -- as opposed to simply a negligent manner (the standard in malpractice cases). Suffice it to say that this is a HUGE advantage if you're the defendant, because the plaintiff would essentially have to show that you weren't even trying to help.

Bottom line: You may get dragged into a lawsuit if you pitch in and the person dies, but in most states it wouldn't likely be anywhere near as costly or difficult to defend as a standard malpractice lawsuit. And as a lawyer, I would MUCH rather be defending the physician who tried to save a life but failed, than the physician who sat off to the side hoping not to be noticed.

And did I mention...I AM NOT YOUR LAWYER AND THIS IS NOT LEGAL ADVICE.