A homeless woman confines an abuser of women in a condemned building, and tries to force a confession, while making a mirror from broken glass.

Convinced that one of the benefactors of her battered women charity is In fact an abuser, a socialite abducts and prosecutes him in a mock trial in order to extract a confession.

The overall premises remind me of the play "Death and the maiden" that was made into a movie by Roman Polanski. The imdb logline for the movie is "A political activist is convinced that her guest is a man who once tortured her for the government."
She abducts him and forces her husband to act as his lawyer in a fictitious trial. In fear of his life, he confess to whatever she ask for.
There is a big difference between the original play and the movie. While the play ends without revealing if whether the accused is guilty or whether the victim is psychotic and misidentified her tormentor, the movie clearly shows that the accused is guilty.

The mirror has a satiric effect. Her abuser? might be both.

Is he her abuser from the present or the past?
How will a mirror force a confession?