I agree with a lot of the people on that thread. It would depend on the nature of the call. If it's not a rush and if it's at the person's house, I would ask the person to disarm and leave the gun at home (complications could arise at the hospital when they don't have anything to do with their gun in a place that has a no firearms policy). If it's not a rush and not at home, I would ask the person to disarm and have an LEO hold the gun until they can pick it up. We could wait for an LEO to get there if needed for a non-rush call. If it's an emergency situation where time is critical, I would ask them to disarm or disarm them (if they're not conscious). If there's an LEO right there, they can hold it. But if not, I would unload it and put it in the ambulance with the rest of his belongings and give it to an LEO ASAP.
I think the only time it gets more complicated than that would be if a person refuses to give up his weapon. That would be the time to call for instructions and CYA.
I say all this not actually working as an EMT, just with certification, so people who have actual experience might have a better idea than me for what to do.
The way I understand it: the way MA law is written - if you are a concealed carry permit holder - and you give up your weapon you (the permit holder) can get in big trouble.
If the pistol is not in direct control of the permit holder (meaning further than arms' reach) and is not locked up - then the permit holder is in violation of the law.
Technically speaking even the EMT or ambulance worker could get in deep doo-doo for handling the firearm under MA law if they are not licensed.
All of this is under the direct discretion of any LEO's who are present - OR - any who may find out about the incident later and decide to write it up.
The over-arching takeaway from MA gun law is: TRUST NOBODY.
I heard this story directly from a close friend: A close friend of his let his permit lapse. So trying to be a good citizen he went to the police station and asked what to do about the guns he had at home. The officer on the desk told him to bring the firearms down to the station and they would store them for him until his permit was renewed. So he did. And he applied for his permit renewal. Then a week or two later he gets another call from the police dept. to come down to the station. So - again, like a good citizen - he did. This time however he gets arrested for possesion and transportation of firearms without a license. Now he is screwed - because he doesn't have his permit yet, and technically he DID possess and transport without a license. Now from what I understand of MA law - it is not illegal to have firearms IN YOUR HOUSE without a license (somebody please correct me on this if I am wrong) - but the problem is that you cannot remove them from the house at all. So (if this is true) - the thing that got this guy was the transportation, not the possession. So the first cop gave him bad advice. Then the second cop didn't feel like giving him a break. And everybody else involved (cops, lawyers, licensing board, etc) this being MA, are like sharks smelling blood when it comes to getting a gun owner in their sights.
So he is screwed.
Takeaway lesson: Trust NOBODY. Your only defense is knowing the law, and sometimes not even that will save you - because nobody else does.
Take MA law, mix in a healthy dose of confusion and ignorance - stir up with angry gun hating liberals, and a crusading cop or DA or two - and your final result is that you are essentially rolling the dice on whether you the gun owner or the ambulance workers will get screwed if an incident like that described in the OP comes to pass.
That is the way I understand life here in MA as a gun owner.