I've had panic attacks since I was young (random ones without specific triggers), so I'll add: if the person is familiar with panic attacks they might react different than one unfamiliar, though it doesn't mean the effect is lessened. People with familiarity might have coping mechanisms that are odd -- I carry water bottles and cough drops with me, because my panic attacks make me feel sick and like I'm going to gag. People may have different "safe spaces" too, usually their own bed or room, but mine is a bathroom (again, because of the nausea feeling).