There may not have been anything going on in the house to cause Thomas to flee. For example, Thomas
might have an untreated mental health disorder which causes him to think and act irrationally.
According to the FBI, the definition of a mass shooting is when four or more people are selected
indiscriminately and then killed. Your source, Gun Violence Archive, counts inner city gang violence deaths as mass shootings. Gang violence doesn't fit the FBI's definition of mass shootings, because it's victims are not chosen indiscriminately. They are usually known to the shooter, but these deaths are still counted as mass shootings by your source. Domestic violence homicides are also counted as mass shootings by your source and they don't qualify because the victims are specifically selected and known by the shooter. Yes, death can be a source of stress for everyone including teens.
VERIFY: Here’s why no one can agree on the number of mass shootings in 2018
Mother Jones has also tracked mass shooting events going back to 1982. In 2018, they
count 11 total not 307.
• Pennsylvania Carwash Shooting in Melcroft PA, 1/28/18 4 killed 1 injured
• Marjory Stoneman Douglas High School Parkland Florida 2/14/18 17 dead 14 injured
• Yountville Veterans Home Shooting Yountville, California 3/9/18 3 dead 0 injured
• Waffle House Shooting Nashville, Tennessee4/22/18 4 dead 4 injured
• Sante Fe High School Shooting Santa Fe, Texas 5/18/18 10 dead, 13 injured
• Capital Gazette Shooting Annapolis, Maryland 6/28/18 5 dead 2 injured
• Fifth Third Center Shooting Cincinnati, Ohio 9/6/18 3 dead 2 injured
• T&T Trucking shooting Bakersfield, California 9/12/18 5 dead 0 injured
• Rite Aid Warehouse Shooting Perryman, Maryland 9/20/18 3 dead 3 injured
• Tree of Life Synagogue Shooting Pittsburgh, Pennsylvania 11 dead 6 injured
• Thousand Oaks Nightclub Shooting Thousand Oaks, California 12 dead 22 injured