My grandfather died at a hospital in South Africa in 1997 after experiencing chest pain. Apparently, he went to reception, and they told him and my uncle to take a lift/elevator up to the ward, and he died in the lift. I was told afterward that it's a no-no to exert oneself during a heart attack. No idea if that's true or not.
Anyway, not second guessing OP, just putting it out there.
Just this weekend I met a relative on the street (mid fifties), doing some shopping. A few months ago, he had some chest pain, his wife thought it was a heart attack and drove him to the ER. As he was being admitted, he went into cardiac arrest, he was resuscitated, and now his four teenagers have their father back, for a few more years at least (he is back at work, and seems to be living a full and healthy life). What's interesting about this, in relation to the OP, is that his wife is a doctor, and she was the one who resuscitated him.
Yes, it's just an anecdote, but a useful one to balance against those in the OP. Obviously the situation differs if you have a terminal illness, or other serious health issues, but I think a blanket NO CODE rule is a little extreme.
Anyway, not second guessing OP, just putting it out there.