To compensate for this movement of ions, electrons have to move in the opposite direction and if the electrodes are connected by a conducting wire running through a useful circuit, that is the route they will take.
That wire can ground a contact on the circuit board behind the light that triggers a function intended to allow the door to be opened with a remote button, bypassing all its security measures.
Peterffy had taken the incoming data wire meant for the terminal and spliced it, soldering the split end into a circuit board that his team of programmers and physicists had built from scratch and embedded into the motherboard of an IBM PC.