Must be a daunting task for Mendes and the writers & producers to rebuild the third act whilst shooting is in progress. It's a good thing that we're now in the dark again about what the finale is going to entail. Will it be a dark, low-key thriller affair, or a 21st century update of hollowed out volcanos and Liparus tankers? I'm excited to find out.
The broad strokes of the third act were settled in October. If they have continued to work on the third act, it has mostly been a case of extended fine-tuning.