While Jamie Dornan may be brooding and mysterious in “50 Shades of Grey“, his intensity is on a whole other level in his role as serial killer Paul Spector on the Netflix series “The Fall“.

The 32-year-old Irish actor went to extreme measures to get into the killer mindset he needed to play the role as well as he did. In a live chat with The Los Angeles Times this week, Dornan said he “followed a woman off the train one day to see what it felt like to pursue someone like that.”

Dornan’s performance in The Fall is critically acclaimed, so these methods seem to have paid off for him. While it may have worked well for his acting career, he did admit, “It felt kind of exciting, in a really sort of dirty way. I’m sort of not proud of myself.” Unlike his character on The Fall, Dornan only followed these women for a few blocks before he changed course. His role preparation methods were relatively innocent, but Dornan still wondered, “Can we get arrested for this? Hold on … this is a really bad reveal.”

The Fall, which also stars X-Files alum Gillian Anderson, has just been picked up for a highly anticipated third season.