Again, no JW I've known would not personally help someone in an emergency situation such as the one in Boston. As for what was done at Bethel, during 9/11 I can't say. I have only heard things....I have no real evidence of what actually happened there. As a former Bethelite, I can think of lots of reasons why they would close their doors when the trade centers were crashed into only a stones throw away from them. Mostly security reasons and protecting the residents of the buildings until they knew what in the world was going on.
As an organization I would say that they are quite unprepared to allow the unsanitary gritty world into their pristine spiritual paradise at Bethel. It wouldn't suprise me to hear that they didn't just fling their doors open and scurry those in need straignt into the Lobby of one of the hotels or into one of the many large cafeterias where food and aid could be administered. For all I know, they may have done just that very thing.