My question here is, if this term is used in other fields not related to fire alarms and emergency breaks.
I agree with Hugo, this phrase seems barely used in healthcare, let alone outside of it.
After reading the link, I understand the concept, but I admit it wasn't immediately clear. A more common phrase with a similar meaning might be Emergency Powers. Whereby, under certain circumstances, special privileges are granted, usually to facilitate a faster response to an emergency.
I don't work in the healthcare field and I've never heard those terms before, but I can guess
If used in a formal context, it might be best to define them the first time, as the avoidance of ambiguity is very important when it comes to fire alarms and emergencies.
However, it may be better just to avoid these terms, especially as there's no results at all in Google Ngram Viewer:
Furthermore, there are only about 1,190 results for "break glass policy" and only about 400 results for "break glass procedure", so these terms are not used much anywhere. I would expect higher results even if they were widely used by the healthcare field.