Most modern democratic countries have a chain of command which can be triggered in case of disastrous events and is intended to ensure the continuity of the functioning of the country.
This chain of command also relies on the fact that there is a plan to get back to normality. This usually means that the person in command has a set of elections to call (at a gouvernemental level) or people are automatically promoted to the missing positions (army, companies, ...).
How would that work with the Catholic Church?
Let's imagine a case that during papal election all the electors (cardinals) die (accident, terrorist attack, ...). Let's also imagine that all of the cardinals are present (which is very likely).
Is there a plan for such situation?
I am curious about that fact because in a democratic country the solution are popular elections (which bring in new rulers), in other institutions people would be automatically promoted to the new functions promotion. In contrast, the Catholic Church only has a handful of electors (compared to the whole Church) and cardinals are explicitly nominated by the Pope (and nobody else).