A good source for searching old New York newspapers is the fultonhistory.com site, or the related https://fultonsearch.org
There might have been something in a smaller NYC newspaper about the accident. You'll be able to tell what area of the city the accident took place, by which hospital the person was taken to, and perhaps locate a likely newspaper that way.

My understanding is that in New York City, newspaper obituaries were not very common, unlike in smaller cities and towns. Since Edward McMahon was Irish Catholic, he may have had an obituary in a newspaper for that community.

As for the wife Rose Bernstein McMahon, she would have been living with her husband at the time of his death, not someplace else. Their marriage certificate, however, would have listed her own address just prior to her marriage. 

You mention that she lived in Binghamton NY at some point. Do you mean that her parents and siblings were living in Binghamton at the time of her marriage? If this is the case, it is highly doubtful that her parents would have run an obituary for their son-in-law, since in your previous post, you said that no one ever spoke of this brief marriage. Running an obituary in a Binghamton newspaper would have been tantamount to announcing to all neighbors and relatives "Our daughter married a Gentile." (except a more derogatory Yiddish word would have been used). But it's still worth looking for, because you never know.
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Michele Lock

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