Turn off the lights by clicking on the light switch next to the door.
Click on the three panels that are lighter than the others.
Flip the carpet tiles around until there's a line leading from one side of the room to the other.
Go back through the door and put the diskette box over the rat hole (click on the diskette box, andthen click on the rat hole.)
As soon as the rat (or head) pokes his head out of the hole click on the diskette box to trap it.
Click on the bridge part (the first ball on the right side), and slide the panels you got earlier into the slots so that they match up with the buttons (the little lines) on the machine.
Let the rat (or head) go in the machine. It will follow the lines and press the buttons.
Next, you'll find that the bridge is to high up to reach it. Click the chair to move it, then click on the bridge to lower it.
Click the keypad on the upper left hand of the door to zoom in on it.
In this puzzle, you have to click on the one key with the picture that's different from all the other pictures. Again, I won't ruin it for you for now.
After you have finished the Intelilock puzzle, go back to the first room you came in and push the cabinet and box to their previous positions, then open the panel that was behind the box and grab the key inside.