That's probably not the argument that would stick as it is patently not what the statute intends, else why would the statute even mention usual and regular duties? First aid is generally rendered in an emergency. However, that argument and others that perhaps could stick would be made and rebutted at very high cost to the defendant in the civil suit.

Lemme putitthisway: "You don't want to be a test case." It costs a lot.

All that said, to qwrrty: Don't take medical advice from a law firm; don't take legal advice from a medical organization. You're talking about my specialty area - risk mitigation and negligence law - and I won't hazard a guess outside my state of licensure as to such an interpretation of MA law, and I sure would not trust a chain of command entrusted with CYA for themselves on the legal front, rather than giving firm legal advice to you. Trust their medical training, but as to the MGL, ask a MA lawyer who researches and handles cases under MGL 112 §12V.