Do files perforate through vertical fractures?

Hi, I was doing a rct today. The patient had sensitivity to hot and cold and pain on biting previously. She had a crack in her occlusal cusp but it did not to spread any further.

When I did a cold test she only had sensitive when I touched one spot on the lingual. Other spots she would not react to the cold.(tooth is upper 2nd premolar)

I started my access opening. And when I hit the chamber there is a dark hole to the mesial. I know this isn’t centered. So I place a file to see if it’s deep and it goes all the way down. I take an X-ray to see if there is a perforation and there is. The file pokes through the side. And I see that I have to extract. Was this hole on the mesial a crack. I feel like I didn’t drill deep to cause a perf but I’m not sure.