Bermuda medical care is very good as is Cuba. It's a matter of distance and severity of medical condition. If I were flying over the Indian sub continent and had a medical emergency I would think very hard on my choice of diversion airports, can I get them on the ground now and have them die or wait and choose a more appropriate airport where the attention may be better. The same in the Caribbean, I would overfly Trinidad or Antigua if Barbados or Puerto Rico were available, but that is just local knowledge.