My daughter was there at the time. She said it was absolute chaos - no one really knew what had happened, there was just an awful lot of screaming, and everyone running. She thought there'd been a terror attack, or something, for a while (perhaps understandably). And she's under the impression the 17 year old was a stranger to the mother/little boy, too, so...
London was very busy this weekend, what with the protests going on, and some cycling event to raise money for charity, and idiots setting off fireworks or flares at Victoria station...
I hope the little boy pulls through - but cannot even begin to imagine the horror, guilt, terror, etc., that his mother will have to deal with, regardless of his recovery, or, y'know, not. 