I come at it differently. I think that there are logical explanations in real time for most/all of the above, albeit in some/most cases building in some logic for decisions based upon lack of depth as well as a reasonable amount of a new coach needing to tinker with new personnel. (However, those are 6 or 7 separate discussions not important here).
I think that it would be logical for PV to play Lurch here. It would not be surprising to learn that he has improved, matured, learned, and grown more confident on a positive trajectory throughout the season which has convinced PV to consider him late in the season as an improvement to Saunders. He gave him an opportunity in Mexico and he demonstrated his development in a live game. PV then clearly had enough collective information to decide to play Lurch in what was, by leaps and bounds, the most important 90 minutes of our season. He was up to the task, and proved to (likely) be an upgrade over Saunders in toto. Therefore, it certainly seems logical that PV would take what might seem like the extraordinary measure of making the change going forward.
In short, it makes sense to me because it makes sense.