I read something about this a while back, but this article provides more details about what Pope Pius XII planned to do in the event that he was kidnapped or arrested by the Nazis.

Pope Pius XII told senior bishops that should he be arrested by the Nazis, his resignation would become effective immediately, paving the way for a successor, according to documents in the Vatican’s Secret Archives.

The bishops would then be expected to flee to a safe country – probably neutral Portugal – where they would re-establish the leadership of the Roman Catholic Church and appoint a new Pontiff.

In the event of his capture, he wanted to be divested of the only thing that gave him any value to the Nazis.  Pretty heroic, if you ask me!

May he be canonized soon.  And may his prayers be with us!