Great Tear Down! Next time just ask for a Twiddler that is unbonded. That way you don't have to destroy the case or the PCB.
The PCB is a single Board made up of FR4 with a strip milled down to a few thousands of an inch so that it can bend. This way we eliminated ZIF connectors and ribbon cables,
It is designed to flex (note: not bend) once.
We did add through hole pads so that you can connect the two boards with wires if the flex connection broke. It is just a 1 to 1 connection. So you should not have much of an issue repairing your board.