Also not a lawyer, but have worked in the nether regions of the medical/legal professions...

As I understand it, the Good Samaritan laws are designed to protect the layperson from *adverse outcomes* resulting from any good faith attempt in providing emergency medical care in time of need. In most jurisdictions there are special clauses specifically indemnifying CPR providers, however the procedure must be done consistent with the training (i.e., if you're whacking someone on the sternum with a hammer you can't just whip out your AHA card and yell "Good Samaritan".) Likewise physicians, EMTs, etc. are not protected if acting negligently or contrary to their training and certification.

It sux that anyone with medical training has an obligation to provide aid if there's a reasonable expectation that there isn't a higher level of medical care available (you see a bad accident, you stop; you see a fire truck you keep going) without the same protections afforded to any other person willing to help.