They didn't wonder about rationalizing the probe's effects because this was a character driven episode. It's all about how the main characters face death. As long as the show isn't actually terminated, then any nonsense the probe does is all good so long as it's cool. Extras are not wanted because they are a distraction from the regulars. And most of the plotting is aimed at getting the key characters into Sandrine's so we can see how they react at the end.