Several years ago flying from JFK to BOM, via LHR on AI, we were pretty much through boarding when the proverbial "Is there a Dr. on board", came over the PA. The gentleman behind me got up and was escorted down to the main cabin (we were on the upper deck). He returned shortly, the plane was closed up and we backed away from the gate. All the while he was shaking his head and saying that we'd likely end up with a dead women on board long before we reached LHR. Apparently a women was experiancing symptoms similar to a heart attack, and the Dr. had suggested we get her off the plane, but the Captain, concerned about our slot, had refused. This being the nighttime rush at JFK, it took us a good 30minutes to get out to the runway, but we finally did, lined up, started our roll. Which was just as quickly aborted. It appears the women had expired as predicted, and she was discovered just prior to take-off. Needless to say, we returned to the gate, she and her family were deplaned, along with all the luggage, etc, and we missed our slot.
As a P.S. this, a friend cut an article out for me that related how an elderly women had died shortly after being removed from an AI flight to LHR. Just goes to show that no one ever 'dies' on a plane.
"The two most common elements in the universe are Hydrogen and stupidity"