So, slow down. Grab your light. And learn to before the arc shows you where it is. Have you ever found a "ghost crack" that took hours to locate? Tell us your story in the comments below.
I walked in and killed the main breaker. I pulled the switch out and held a magnifying glass to the side of the nylon body of the switch. There it was. A crack no wider than a human hair, running from the hot screw to the ground yoke. see electrical crack
Here is why finding that crack before the power turns on is the most important skill in the trade. So, slow down