I always think it is amazing how many buy into the lifes at risk hyperbole. Even if we assume that the content in the document isn't already known to all the "players" in the field, how much "advantage" can be gained from the manual (I suspect if it really was that important they would not put it in the manual). Moreover, if leaking the manual really puts the lifes of the crew at risk, would not leaking also put lifes at risk, i.e. the one of the people fighting the tanks?