Its a good point, on long haul most diversions are for medical reasons, it was put forward once of twice that an aircraft of this size might justify a trained nurse on the crew as part of the cabin staff. As far as airfields go, most airfields can accomodate large aircraft in an emergency, they may not be able to provide pax services etc, and it may block ramp/apron access to other aircraft. The 380 has already been to Iqaluit for cold weather tests, this airfield would very definately only be used in an emergency.