It's pretty incredible how ingenious people can be when they have a problem they need to solve. You think that there's an invention for everything, but there's not. It's up to people like us to constantly create new inventions to make the world a better place, or in this case, repurpose another invention for your needs. What we have here is one of those toys balls that expands and contracts. This woman, fearful of having people close to her, turned it into a protective shell.
I totally get where this woman is coming from. The subway can be a weird, touchy-feely place. Having some kind of protective shell has its benefits, but also, if being around people is that big of a problem, take a taxi. Don't make YOUR crazy a problem for the rest of us.