Allowed Freak Outs

OK, what justifies as a legitimate freak out? And when are we allowed to do them? I was in Target with my girls just this afternoon when I leaned over to look at one picture, I say one, because in that time my eldest daughter started choking my youngest one...needless to say I freaked out. I tried to smack my daughter's hand away from the little one's neck. Is that ok, is that legitimate, when you think one of your children may die is it ok to freak out?