The guy was pointing the gun at the interviewer at first but lowered it because he realized the camera man had the camera pointed away. He waited for him to swing it around so they were live on air, then shot them. The sob is a psychopath, well documented by his supervisors in two different jobs. Wacko to the tenth degree.

Nothing would've prevented a tragedy like this. If guns were banned, he would've used a gas can and a lighter. Nothing can stop attacks like this, especially to people who's job is to provide news in real time. They are laser focused on the interview, and so is the camera man and the person being interviewed.