Flip the mirror and shine the light at the ceiling (or sometimes the floor) and the fully refelected image will overwhelm the front-surface reflection so you can see the ceiling.
(the fully refelected image; will overwhelm; the front-surface reflection; so you can see the ceiling) (you; can see; the ceiling)
the fully refelected image you
will overwhelm can see
the front-surface reflection so you can see the ceiling
the ceiling