Wow, this is an odd thread. Firstly, I don't think it's fair to criticise the nanny for allowing a child to run ahead of her. You can't keep children constantly by your side. Secondly, it's wrong to speculate either way on what may or may not have happened. Clearly the nanny thought something was amiss and as the only witness, you've got to give some weight to that, so best to be cautious. That said, based on the account, it is possible that all was not as it appeared and so we shouldn't overreact either.