She had no face. Just a mirror reflecting the world surrounding her. A mere reflection. She looked up into the shattered mirror and flinched. It reflected something in her and made her recoil. She quickly turned and walked away.
"broken windows" : take frosted contact paper and cut it apart to look like fractured glass. The semi-transparent frosted contact paper takes on the appearance of the "glass" while the actual glass pane (which is transparent) disappears.