Where did you get this from? I know "Drama CD" but ive searched for all 5 and this isn't on them afaik, and its not on the 4 das finale drama cds either.
My favourite detail is Aya wanting to do Nindo for the shurikens while the Hippo Team audio drama has the history girls lamenting that their first year Nindo elective did not contain shurikens
The drama CD and MLLSD really demonstrate that Karina is the heart that drives the first years. It's her own love of movies that she spread to the others (which is made quite evident in MLLSD), and this show that it was that same love that first drew her to Senshado, eventually getting the others on board. It's quite fitting then that she became the driver of their tank.