Although this massacre was indeed one of the MOST horrendous that this country has known,,,I can honestly say one thing,,that it WASN'T a " cold,calculated " one.
Instead,,it was initially a" drawn-out ", on the edge killing,,carried out in a frenzy with thoughts of loathing,,feelings of despair,,being let-down,,along with a conglomeration of thoughts and experiences from the past which sadly all came to a head. A conclusion which is positively and most definitely possible.