I'm only writing this because I feel like I need to after yesterday evening.
Advices aren't for people having panic attack. I don't even know if it's possible to do anything in such case. I can't.
It's for people around that can see someone having a panic attack. For those who can support.
It's based on my own experience, and I am no expert. It simply is what I think, in my case, might help. Each person is different so don't take it for granted that what I say works the same for everybody.
I'll repeat it once again but it's only some advices based on my own experience, and I may not have much.