Oh, well, as long as you're redoing most of the drywall anyway...
Wusses.
If you have to cut into a wall that you know, or suspect, has live wires inside it, use a utility knife. Not a saw. A utility knife won't extend through the drywall far enough to hit a wire, and even if it does the wire will simply move out of the way.
wanted to buy a gun.
That's up to you. Certainly it's safer to kill the power to the panel first, but if you're careful about where you put your fingers it's only slightly safer.
At SWMBO's insistence, I never work in live panels alone. And at *my* insistence, SWMBO never works in live panels at all. She knows what she's doing (degreed engineer). The issue is that she knows CPR, and I don't.
Another rule of thumb is to keep one hand in your pocket or behind your back. If you're wearing rubber-soled shoes, it's nearly (but not completely) impossible to get a fatal shock if you have only one hand in the panel. The greatest danger in AC comes when the current passes across the heart: from hand to hand, or from hand to opposite foot. I've been stung a couple of times; that encourages a healthy respect for 120VAC, but it also helps to dispel exaggerated fears of it too. The last time, about five years ago, the back of my hand was against the panel chassis and I inadvertently brushed the tip of my index finger against a live busbar, so the grounding path was just the length of my finger plus half of my hand. I felt it up the the shoulder; half an hour later, I could still feel it in my elbow. It *hurts*. Make no mistake about that. But I'm still alive.
You're quite welcome, Bill. Keep asking questions -- it's the best way to learn.