This is a topic of much contemplation for me. I'm not trying to sound like a prick, but, she CHOSE to go to the event and she has to live with the consequences. To me, if there's a chance you're going to have that happen, it's unfair to everyone involved: the worker now has (to try) to help, your whole group has to deal with your panic attack and try to calm you down after leaving, the people behind you are now going to get held up as your situation is handled, the scare actor who did this to you probably feels QUITE guilty, and most of all, it's unfair to yourself! to put yourself through a massive panic attack isn't ok, your body does not need that stress, so to put yourself through that just so you can go with your friends is a terrible idea. This is coming from somebody who often has panic attacks and, from time to time, they are quite extreme (physical scares don't cause them, it's more of a mental thing for me.) BUT, there IS one group of people who should feel horrible for her having this panic attack and that group of people is her (neglecting) friend(s) that talked her into going to hhn, because I guarantee it wasn't her idea in the first place.
All I'm saying is, if I were you, I wouldn't feel bad at all (though I understand why you do.) I would simply have been very judgmental of the people she chose as friends? I for one can say that if my friends brought somewhere, knowing that it was likely I'd have panic, they wouldn't be my friends much longer. Sorry for the rant, but this is a common thing that happens at hhn and it aggravates me.