Note re: Bleeding.
You may have to do it a second time anyway. The threaded rod, ball bearings, needle bearings, washers and snap rings inside for the internal parking brake mechanism often capture air bubbles. Vigorous yanking on the parking brake handle and kicking the brake pedal during the bleeding process may help. If not, a short drive will do it. The amount of air "stuck" only leads to what feels like a slightly long pedal, not a severely spongy one.
Results of unscrewing the brake lever arm bolt (without internal stop) can be "mild":
or can be severe:
If you must do it, use vise-grips or something to hold onto the arm itself. However, in all cases I know of the brake cable has enough slack to pull and unhook from the arm.