I gather you are knowledgeable enough that in case of an emergency outage you could grab a piece of cabtire with a plug, disconnect the BX from the furnace and hook up the temporary cabtire. Reverse when the power comes back on.
You could make the procedure simple for a less knowledgeable person by throwing a junction box and DPDT switch into the mix.
However the inspector also has to consider the house being sold and a totally clueless person misunderstanding the system and burning the house down.