With the latest DVR pre-release, you can now load movies and episodes with the full player via a URL as well.
/admin/movies/$file_id/full
/admin/shows/$show_id/episodes/$file_id/full
And there's an even shorter helper URL to play back any file:
/admin/files/$file_id/full
Additionally, you can now launch items into the full screen video player via the Watch modal.