I live in West Anchorage about a mile and a half from that corner.  I happened to be awake with the windows open and heard that shot.  I thought it might have been fireworks, until a while later I heard a multitude of sirens.     A lot of homeless people hang out around that area during the day.   I have no idea what type of people hang out there at 3:00 in the morning , whether it's homeless people or otherwise, I don't know,  but apparently it's not a good crowd.