I see on the LGA passur tracks beginning around 14:40 an A319 arriving from MSP, NWA506, descending as low as 1400 ft for runway 4 at LGA just to the east of the Cirrus who was northbound over the East River at around 34th street -- then NWA506 began a climb back up to 4000 ft for a go around, overflying LGA, then turning left 180 for the downwind south over Manhattan, landing at LGA at 14:57.
Any way to find out why NWA506 did not land on the first approach? Were they ordered to climb and go around in order to accomodate an possible emergency landing by the Cirrus at LGA after a mayday call?
The pax sitting on the left side of the A319 would have had a clear view of the Cirrus crash at an altitude of 3000 ft, unless already in the clouds.
http://www4.passur.com/lga.html
start at 14:40