Bad Education - Rotten Tomatoes
Alma movie: 187 (1997)

One could possibly argue that the actions of substitute teacher Trevor Garfield (Samuel L. Jackson) are in the best interests of the "good" students at his school, or that his eye for an eye tactics are understandable, considering he himself was once violently attacked by a rebellious student. But you've really got to draw the line somewhere, and that line is somewhere on this side of tranquilizing a teen via bow and arrow and cutting off his finger, or indulging another in an all too real game of Russian roulette.