I looked at the tape and the shooter seemed to be 1 of a three person group that was arguing with a 6(?) person group & had actually walked about 20 feet away. The larger group grew to maybe 12 or more & were pursuing them.
if (big if) I'm viewing this correctly in most of the US the shooting would have justified as self defense against imminent death or bodily harm.
At any rate this is just another reason to bet with an ADW and not to visit the track.