Actually, this will end up calling your myCamera.setMode() over and over and over again while menus are being drawn... You want to add something like....

    if (state == MENU_ROW_PICKED) {
        if (::renderFirstPersonOn) {
            myCamera.setMode(CAMERA_MODE_FIRST_PERSON);
        } else {
            myCamera.setMode(CAMERA_MODE_THIRD_PERSON);
        }
    }