Not sure it's a factual error, but I'm not sure the geography works out.
In The Killing of Georgie, they leave a Broadway show, and we hear that 'a gentle breeze blew down Fifth Avenue', presumably marking the spot where the next thing we hear is that they have been attacked by 'a New Jersey gang', coming out of a darkened alley.
So why does the ambulance go to 53rd & 3rd, a place famous for gay clubs, admittedly, but some way on from Fifth Avenue?
There don't seem to be many alleys near 53rd & 3rd (though much of it has been redeveloped since the mid-70s).