It is not uncommon for loners to sort of lose it and become so unhappy to the point that they finally snap lets say and decide to take out their frustrations of being so unhappy in life against everyone they believe has wronged them and anyone who gets in their way. Charlie Manson is a pretty good example of this.
Which is why we as a society need to keep a better eye especially on kids who struggle to be social and are either isolated voluntarily or by others. And see if we can reach them before their isolation gets to the point that they can’t take it anymore and take it out on anyone who comes near them. Which I believe is the boiling point that Samantha Bachynski reached. And then coming across a young man who just got of prison and is starting to go psycho himself just made of a deadly combination here.