I made a picture of Mary's present and past self. The one on top is her past and the one below is her present. Flip the picture upside down to see the rest of the message.
To explain the message:
Present Mary can see into the future, so she's able to tell what's going to happen before the others can. Past Mary worked as a security, and that allowed her to have access to all the rooms in the building (looking through the cameras). She could see what others couldn't, not even Norman Polk.