If you include an Open Work Permit (OWP) with the Inland application, and submit them both before your visitor status expires, you will then have `implied status' that carries you throughout the PR process; it means that you can legally remain in Canada while you wait.
If you do NOT include the OWP, you do NOT get implied status and must either extend your visitor status (which can be done online), or leave and hope that you are allowed to re-enter Canada. If you leave and are denied re-entry it could jeopardize your entire Inland application.