Is this a hypothetical question or an actual call? If someone cut a cable after the walls were closed up it has to be in an accessible spot. If this is new construction and the vandal did this at the FEPAC before the rock went up it might be as easy to fish in a new wire around the bad spot than to get in there. You should be able to get some help in the routing from the original EC ... if he is not the one who cut the wire.
