Okay, time to play with the lever and switich some more.
Let's move the lever to Red and flick the switch (it should be at "o" now).
There are only 6 combinations possible, it would seem. Red o, Red -, Grey o, Grey -, Blue o, Blue -. One of them should work, right?
Here is a chart with what happened:
Blue o (Fan @ Steam, water on)
Blue - (Fan @ Steam, water off)
Grey o (Fan @ Metal, water on)
Grey - (Fan @ Metal, water off)
Red - (Fan @ Laser, water off)
Red o (? ? ?)
There are also the end positions (far left, far right) but they appear to be neutral settings. Still, there is a possibility that the answer is to have the lever in either of those positions.
The only other course of action would be to increase the power level in the Metal Room, but that is already dangerously high. I would rather leave it where it is for now and test this first, especially given the warning about misusing the panel. By the way, does anyone recall what power level in that room was at last?