It has happened so infrequently that it rather highlights it as an unusual choice of question - why not a terrorist incident, foreign war, natural disaster or i

It has happened so infrequently that it rather highlights it as an unusual choice of question - why not a terrorist incident, foreign war, natural disaster or incident with a Royal? You would almost suspect that they are trying to select individuals who have a natural instinct to maintaining current power structures, but clearly that is nonsense and what they are looking for is a carefully reasoned response.