Talk about in the dark. When working on The Terminator, Arnold Schwarzenegger learned to shoot a gun — blindfolded.

The action star opened up quite a bit with some revealing details in his new book Be Useful: Seven Tools for Life, via Insider.

The book is geared towards helping people better themselves by being a part memoir, part self-help guide. A section of the book that sparked much attention is where he revealed how intensely he trained for his best-known role, The Terminator.

“On The Terminator, it was becoming a machine: blindfolding myself until I could do every gun stunt with my eyes closed, and shooting so many rounds at the range that I no longer blinked when my gun fired,” he wrote.

Regarding the second installment of the series, the training didn't slow down in intensity.

Schwarzenegger wrote, “On Terminator 2, it was practicing the shotgun cocking flip so many times my knuckles bled for what amounted to two seconds of screen time. I didn't complain.”

A lot of his work ethic boils down to discipline. He explained in a recent interview.

“Overall, there was discipline in the house. You don't turn out that light? I will unscrew those light bulbs and you will be going into that dark room at the age of 3, and you'll be scared. So you better start learning to turn off those lights,” the 76-year-old revealed on Rich Roll's podcast.

Arnold Schwarzenegger is one of the most successful people out there. Beyond film, he was governor of California and one of the most iconic bodybuilders ever. It's interesting to read about the lengths that he'll go for perfection, whether that be pumping iron or a shotgun cocking flip.

Like The Terminator, we might “be back” with more revealing details of his book soon.