This is of course a problem and I personally would solve it by adding that the Alpha Legion is pretty adept at also keeping their own members in the dark to the grand scheme. The character will likely have been given alot of information but it could be worth for the GM to point out to the player that the characer may not have been given the entire picture by the other members of the Legion, and they probably don't known exactly what's going on themselves with 100% accuracy even while I as a GM do have an idea about what the Alpha Legion's state is in my games. But I understand that some people might want to spell things out a bit in detail.
I would say any member of Alpha Legion would understand and trust in the fact they are not fully informed on what is going on. That they are operating under vauge, misleading, or patently false parameters, all with the knowledge that their superious know what is going on and will do what is needed. The bosses know that the cells are operating in the dark and they take that into account with plans that are flexible and adaptable to almost any occurence.
There is also the question of whether any Alpha Legionnaire worth his salt would believe he's being told the entire picture or not being fed disinformation. And then adapt accordingly.
Pericula in mora
Danger in delay