"I do not know. All I can say is that the ending of the Time War was not only a Fixed Point in time, but it was also Time Locked, and the Doctor managed to find a way to change the ending and save his people. Q might know this which is why the mes in the boxy form are inaccessible."

But her tone suggests, there might be other ways. Between the Doctors and herself, they might be able to find a solution.