I was wondering that as well, I would hope I'd not get into a blind panic but not sure I'd think to get my camcorder out.
I do wonder about that like some people took at the us campus shootings and such and other awful happenings.
I guess it may help the authorities afterwards which could be a good thing but I can't help thinking could they be helping rather than filming.
I'd maybe do it if it's something that could lead to helping in a way like indentifying a terrorist or something.