Outside/ inside

This little pantomime occurs at least once a day in my house.  Murphy, the big cat, has been outside and has now jumped on all the windowsills of the house to see which room I am in so he can bang on the window until I let him in.  Meanwhile, Anastasia, his little sister, has been tracking his progress around the house from the inside.  Every time he appears on the outside window ledge she jumps up onto the inside ledge and starts scrabbling at him on the glass.  I know what he wants, but what on earth is going through her little mind?  Is she teasing him?  Attacking him? Trying to rescue him?  Trying to work out why she can;t reach him through the glass?