Tower Level 3

There is something i'm missing.

Im at Tower Level 3, did clean the floor of all enemies. Did find 2 switch and a locked door.

The door saying i do not have the key to get through.

I tried multiple combination of the 2 switch i found but no difference from my perspective.

Did i forgot a key somewhere or there is something about the switch i did not understand?

And the strange message at the entrance, Enter if you can see through walls...