Killing two people and injuring one is a “mass shooting”?
Not according to the FBI. A 2005 report classified a "mass murderer" as someone who kills 4 or more people (not including himself/herself) in a single incident. Longer running killers (eg. multiple incidents at different locations & times) get labeled spree killers or serial killers (even longer term).
But a few incidents are all it takes to grab headlines and try to push a disarming fascist agenda. Most (57% last I checked) of the roughly 30,000 deaths per year in the US by firearm are suicide. Also included in that number are accidental deaths and justifiable homicides (both by law enforcement and civilians). The actual number of homicides by firearms each year is considerably lower. Even smaller still is the average number of people killed in "mass shooting" incidents each year.
But they need fear to stoke their agenda. Let's have some fun with numbers though to assuage those fears with facts. Each year in the US about 20 to 30 people are killed in "mass shooting" incidents (4+). How afraid should you be? Well, if someone wants to kill you, a mass shooting is not terribly likely to be the tool of choice.
In other words, people are getting killed all kinds of crazy ways. Your chances of being killed in a "mass shooting" event are so far down the list it literally is not worth worrying about. You want to be concerned for your safety? Worry about your commute to/from work today. You are far more likely to be one of the roughly 30,000 traffic deaths this year than the 30 mass shooting deaths. Oh, that's right. The media can't use traffic deaths to push their disarmament agenda. The would-be fascist intelligentsia want obedient slaves that lack the means to revolt.