My point is that the policy in those countries intentionally does not try to define what exactly is "the broad case" (because, frankly, any definition will have

My point is that the policy in those countries intentionally does not try to define what exactly is "the broad case" (because, frankly, any definition will have its flaws in some unforeseen and unforeseeable cases) but instead devolves that decision to the doctors, so that every case can be treated as a "weird case" if and only if the doctors say so, because the policy in these societies is that they trust the doctors to make the proper ethical choice more than their ability to prescribe exact criteria in a legal act. In essence, allowing these cases to exist at all means that the law acknowledges that it can't explicitly state in legislation beforehand which cases will need bespoke review and which will not; and that it in such cases the law does not prescribe the final decision but devolves it to the medical specialists who see the individual case. An alternative that I've read about from recent events in USA with hospital lawyers being present in emergency room to make a decision when a certain intervention (deemed necessary by the doctors beforehand) becomes "permissible" seems literally incomprehensible and insane at least to me, as from all the people in that room they are the least appropriate, least qualified, and with least moral rights to make a decision about what should be done or not - if you don't trust these particular doctors with doing what's right, you shouldn't let them perform operations on people at all.