I'm not sure if the described method of leaving the B section of the map is out-dated or what but nothing like that seems to happen for me. I count at least four diamonds (white, blue, yellow and orange) a fifth one (also orange) at least seems to appear after using the action button (hard to keep track of them so I am not sure if it was always there). they only respond to the crossing effect. White one will flicker and jitter about. One orange one will spin in place. The other orange one will flash colors and spin in place (almost as described). The others will stop completely still. None of them, however, in ANY of the listed states will send me back to the previous area.