He didn't seem overly scared to me but being scared is always a factor. Appeared he did not see a weapon and decided to hold back, likely based on information he did have.
It goes both ways. Shooting someone to death before a weapon is ever seen can also be quite problematic for the shooter. Even though he was legally justified here.
The cop told the suspect he didn't want to shoot him but would if he had to. The suspect is telling the cop, "Shoot me" repeatedly but never produced a weapon.
It's human nature not to be too quick to take a life. It even happens in war. Its a moral thing. It's hard to completely train that out of most people.
When someone says “I’m going to kill you” it’s best to believe them. It’s not a good idea to hope that they don’t.