Do you not realize that bullets go through walls? Luckily it was contained but could have easily turned into a tragedy if some toddler sleeping next door gets hit by a stray bullet. You are arguing semantics, just because it happened at someone's home instead of public doesn't not make it a mass shooting. You just want the numbers to look better so you can ignore certain types of gun violence. When in reality it should be lumped together because it is a systematic problem that needs to be fixed.
It does though, because certain types of shootings don't put the public at risk. A shootout between two rival gangs is not the same as some psycho shooting up a grocery store.