Have a look to an alternative opening procedure.

Take the flathead screwdriver.

Insert it into the slot located at the bottom of the handle and turn counterclockwise to release the bottom cap.

The second image shows the amount of turning needed to loosen the bottom cap.

Be careful with this as the plastic is not very solid. Deforming the material could result in issues when placing the device onto the charging station.

Hold the handle upside down, and push down on the shaft to release the internal components of the handle.