How old is the wire run and did you try a megger on it? A plain multimeter at the panel won't show a high resistance short to a stud, but a megger will light it up because it pushes real voltage through and the nick arcs over. I had one just like yours where the reading looked fine on the meter but the megger pegged it, then I used a tone probe along the wall and could hear the signal change right where the drywall screw was. If you don't have a megger, an insulation tester rental for a day is way cheaper than cutting open a wall you didn't need to open.

How did he get the stick to stay without cracking the spine?

Master hand tools first, then jig becomes faster too.