Having been the "is there a doctor on board" doctor before: you make the call based on what's in front of you and the turmoil that would result from a precipitous landing. The case I had to be involved with was a relatively uncomplicated chest pain. I couldn't rule out angina, but the patient was stable and they had aspirin and it started halfway into a 4-hour flight. The patient remained stable all the way through and I released the individual to EMS on the other end. I don't see what an early landing would have bought in my case, and I'm not sure what it would have bought here.