Huh, this is an interesting question.
I haven't had a serious panic attack in ages, but when I did it would be something would set me off, like a balloon popping or a car backfiring. One time I was in a sculpting art class where we had to use the table saw to make something for our project. I was fine when I was the one handling the saw, but then someone set up the saw in the station behind me--which in retrospect seems like an unsafe setup for a shop if the blade isn't loaded correctly, something could go flying and the person behind them wouldn't have any warning-- and they turned it on when I didn't know they were there. I flipped out. I remember freezing, very carefully turning off my saw and following the safety procedures for shutting down. The next thing I knew my boyfriend found me in the dark room huddled under one of the cubicles that housed the enlargers in the photography labs on the other side of the building. I don't remember leaving, I don't remember walking over that way, I don't remember anything but huddling in a dark, little cubby the way I used to hide under the bed or the in the closet when I was young. Someone popping a balloon behind my back can cause the same thing although I've gotten better. The last time a balloon popped I didn't blank out, I just nearly crawled into the lap of the person I was sitting beside. The good news is, I wasn't alone on that at the time, I was manning a booth at a festival with a former cop and veteran. We were all having a hard time of it to be honest. You could just feel the collective flinch any time a kid walked by with a balloon. Being with people that you can trust to anchor you in the now, or who know how to keep you safe when you know you're likely to be exposed to triggers helps a bit.

I don't have an answer for this question. I hate the sounds of things, balloons and fireworks. I spent years taking a sleeping pill so I wouldn't be awake during the week of the fourth of July. Unfortunately, or maybe fortunately I don't know, my current job is at night, so I had to be out and about on the night of. I was doing really good about being okay with bangs if I was in my house, so that I don't end up dropping to the ground and army crawling to the tub or under the table. I managed to brace myself for the fireworks I could hear in the distance. Unfortunately, one of the neighbors was setting off fireworks in our driveway, and I didn't know they were out there until the fireworks went off right as I walked out my gate. I don't remember getting to work, and I was halfway through my paperwork when I realized where I was. I was trembly for the rest of the night, and I ended up taking a muscle relaxer to get through the rest of my shift. I honestly don't know what to tell you about this. I forced myself into limited exposure over the years until I was able to go outside during a fireworks show, but if a noise happens that I'm not expecting I immediately go into like Nam flashback mode, or apparently black out and run on autopilot. Since I can't know when I'm going to get triggered I can't know I'll need medicine for it, and I don't have episodes very often or without triggers I'm not willing to go on maintenance drugs. However this is obviously still a problem for me as well.

I will be very eager to see some responses for this question.