When Red has obtained the rock hammer for Andy he get Brooks to give it to Andy When he's doing his rounds with the book trolley, after Brooks has handed Andy the hammer (and a book) he continues walking out of the shot to the right of Andy's cell. But Andy's cell is the last one on the row, beyond him is a wall, where is Brooks going?

PS. How does Brooks do the rounds with the trolley by himself (he says he's never had an assistant)? There are no ramps up to the different levels and he couldn't have lifted it up the stairs.