I watched the screening of this movie about one month ago. The prisoners in the movie had practiced in a very sincere way. Here are just some quotes from them (I don’t remember the exact words, so it is more a paraphrase):
“it is ok if i don’t get out of here for life. But it will be very sad if i die without having known my self…”
“just sit, have the courage to face myself”
Just these already made them far better than many Buddhism teachers.