I am not entire sure that I follow the question, but it sounds as though you are asking whether or not an internal user can access the WSS site without needing to use ADFS. In this case, the answer is unfortunately no, when the site is configured for ADFS integration, all authn/authz must come through the ADFS servers.
So in short, even though your users are internal, they still have to use ADFS to access the site.