Workplace Violence is a tragedy beyond words. It is one of the most devastating experience someone can go through. Personal Safety within any company and even our schools, is not the job of the Security and Safety Personnel, it is everyone's job. Until people figure this out Workplace Violence and School Violence will continue to rise, and this is sad.
People have to speak up.
They have to tell someone when they hear violence rumors. Companies also have to take a stand. You will be shocked at this answer. We will never know. Given Antalik's state of mind it would have happened somewhere.