We used to run a haunted house. Mostly geared toward 8 to 13, but we had several adults completely freak out and have to be escorted out and the last year we ran it we had a HS football palyer friend of my DD's have to go home and change his clothes after only making it half way through.
I worked the front door and no one was admitted without them repeating the rule "Touch NOTHING and NOTHING will touch you".
I completely understand someone KNOWING that everything is fake but still freaking out. Shoot, it was my house and there were a few times I was in there alone and got pretty spooked.
So I can understand anyone's initial reaction is to fight back if touched, no matter what type of training they have.
For the people volunteering in our house, we always made sure they understood that if a guest was really freaking out, to drop out of character and help them out. The reason I dislike commercial haunted houses is they train their people to almost pray on the most freaked out of a group (which is usually me) to up the fear factor.