SBCL break into debugger giving a REPL even if the debugger was previously disabled

break.lisp

(restart-case
    (progn
      (setq sb-ext:*invoke-debugger-hook* nil
            cl:*debugger-hook* nil)
      (break "~S" variable-of-interest)) ;or just (break)
  (exit ()
    :report (lambda (stream) (format stream "Exit with (sb-ext:exit)"))
    (sb-ext:exit)))

script-debug.lisp

;; Or, simply
(setq sb-ext:*invoke-debugger-hook* nil
      cl:*debugger-hook* nil)

(setq sb-ext:*evaluator-mode* :compile)
(declaim (optimize safety debug))