You also have to remember Al, and I agree the movie did a poor job of explaining this, her mind and memories are warped from experimentation. She could have plenty of other stuff in her head and just not know it. Maybe a flashback or two to the original TV show would've helped out on this point a bit. If you ever get the urge, the whole River story makes *alot* more sense if you watch the show. You'll understand her frame of mind and why she can't come up with information intentionally.