Credit belongs to the themindisacity and their detailed walkthrough.
In the very last scene of Act II, in the Control Room, one must solve the switches puzzle to progress without skipping through it. The solution is:
- The yellow and red levers must be in the downward position
- Green lever must be up
- Left switch is to be pressed 1x so that its color is green
- The right switch pressed 2x to become red
- Select exit left to end the act and obtain the Master of Switches achievement
* (If this is your first time through, you will also obtain the Hussa - Get On With The Plot! achievement after Act III's opening scene concludes)