Desertia.
It all depends on the advice that the doctor gives. If the advice is "we need to get this aircraft on the ground asap to save this life" then that is what we would probably do. If the advice, as it was in this case, was to give up when SOPs say to carry on giving first aid, then the crew will carry on.
I hope you can see the need for the SOPs as legal protection for the crew (and also for the volunteering doctor.) The SOPs are constantly reviewed and are changed if the procedures are not robust enough.
Thats my last on this subject. Back to hoping that all our cabin crew still have jobs in a few months time.