I don't get it: what is the other interpretation, beyond "two people and some onlookers"? Clearly George cannot be "a policeman and several onlookers". And the

I don't get it: what is the other interpretation, beyond "two people and some onlookers"? Clearly George cannot be "a policeman and several onlookers". And the added comma, as said in the article, transform "a policeman" in an aside.