Okay, so:
You will need a screwdriver, crowbar, and wirecutters/preferably multitool. And a door, of course.
First, use the screwdriver on the door to open the panel with the wires.
Second, take out your wire-operating tool.
Now, there are two wires of interest: one that's obligatory, that being the 'Test Light' one, and the other, optional, is the Bolts one.
You will want to pulse/cut and mend wires until you can find the one that causes the Test Light to be off. If you haven't fried yourself, mission accomplished, just use a crowbar on the door to open it.
Now, if you used the wirecutters and the Bolts fell down, you dun goofed. You will have to wait until they get back up, or find a multitool and pulse the wire you used.
There is also a supah seekrit technique: aside from the other two, get a Remote Signaling Device if you have the Signaler on your PDA (Scientists, for example, have it).
Set a non-default code/frequency on the RSD, screw the door open, attach signaller, go to PDA, send the proper code on the proper frequency. This way you cannot get zapped (I think), and you can experiment with the wires AND, if you find the right wires, you can leave the RSD there to gain remote control over the bolts/open at will if you have the crowbar, for respective wires.
Seekrit trick 2: drink a shitload of Kelotane, then get zapped to your heart's content without any damage.