In order to secure the loose potentiometer I needed to pull the knob ends off of their shafts and then work the board off of the tapered ridges around the module.

Hold each shaft near the circuit board and firmly but slowly pull each set of knob ends (black end piece with a clear piece and a thin gasket) away from the shaft.

With the knob ends removed, carefully work the circuit board out from behind using a plastic spudger or similar tool at the board edges.