One scene required Louis Fan and Yukari Ôshima to exchange lines while standing close to a raging fire. Siu-Wong, doused with water for protection, was horrified when he noticed Ôshima's exposed neck literally smoking and blistering from the heat. When he asked her why she didn't move, she reportedly replied, "You weren't done with your lines, so I had to wait for the cut." Amazed by her professionalism, he referred to her in future interviews as "amazing Yukari."
So much fake blood was used in the "Meat Grinder" finale that Louis Fan could not wash the red off his skin for three days.
The first Hong Kong film to be passed with a 'Category III' (18+) rating for violence.
The shelf behind the assistant warden's office is filled with pornography films.
In the English dub, the prison gang leaders are called the "Gang of Four." In Cantonese, they are the "Four Heavenly Kings".