So the part on door hacking seems to be outdated. I haven't looked into the code but after spending a while messing with a door I've found that the power wires are different from listed.
how it actually works:
There are two Power A Wires, and two Power B Wires.
power A wires - when pulsed, remove power to the door for 10 seconds and when cut, remove power to the door for 10 seconds, IN ISOLATION (test light off, AI control light on) power B wires - when cut or pulsed, do nothing, IN ISOLATION
when you cut both power A wires, the power to the door is permanantly off. (test light off, Ai control light off) when you cut EITHER power A wire, AND EITHER power B wire, then the power to the door is permanantly off. (test light off, ai control light off) when you cut both power B wires, nothing happens.
if you pulse a power A wire while either (or both) B wires are cut, then it removes power to the door for 60 seconds instead of just 10 seconds. (test light off, ai control light on)
so all power wires do *something*, there are no actual dummy wires in doors.