I heard that R Zelig Epstein was asked how did Mir Yeshiva decided to travel through USSR in apparent violation of Daas Torah of R Ozer who apparently advised them not to go. He answered – it was not a problem because this was before the Daas Torah…
Given that Mir students were getting Sugihara visas up to September 1940, and R Ozer was niftar in August 1940, it seems that DT was not yet operational during R Ozer’s lifetime. Maybe, out of modesty, the Rav authorized DT to start after his own petirah so that people would not think that he is doing it for his own aggrandizement?!