I may not be the best person to ask as in the past I had a tendency to try and leave moving objects (even a plane once) — I guess a bit of claustrophobia and a pretty strong attraction to drugs will do that to you.
But now honestly — I just stop everything I am doing and breathe. Sounds cliche, but most clichés have loads of truth to them. Once I chill out I also ask myself what I was doing in the moment that led to these feelings and also what decisions I made leading up to them. For me, my lifestyle was the root cause and simple things like getting a good night sleep and eating well made me feel a lot better. My last attack was about 9 months ago and was due to not sleeping well with a baby in the house — so I started going to bed earlier. Nothing ground breaking I know, but most of the time the little things take care of the big ones.
Hope that answers your question Nikitha