The rescue script is essentially a way to manage your WordPatch installation and it is needed because WordPatch does not rely on the WordPress API. It is commonplace that through the modification of core files a user might accidentally break the WordPress admin panel dashboard temporarily. The rescue script reimplements each of the required APIs and therefore is resilient through such breaking changes. In addition to providing you with an alternative way to manage your WordPatch installation, the rescue script controls the mod runner and therefore is required to ensure mods run automatically after WordPress updates.