Leave the previously used tool wedged in the device.

Insert another plastic opening tool into the bottom of the left side, as shown.

Using a similar procedure to the last step, run the tool along the side and widen the front panel-back panel gap. This time, run the device from bottom to top.

Repeat this process for the right side of the device, starting at the bottom of the right side.

Some of the other tools that you wedged in may pop out. Simply wedge them back in where they were previously, and continue.