Were I to get stuck out in the open where I had to go be amongst the public during such an event, I would be looking to grab a few good tyvek suits, a full face motorcycle helmet, and a few goodies from the local hardware and electronics stores. Those ought to be reasonable, maybe the tyvek might be a bit of a challenge, so it pays to locate a supply nearby now and keep it in mind if the time comes.

That's about the extent of it I reckon.