Referring to his instincts, the guy in the car was going to run. The cop guessed right that he was up to something.
As far as the cop shooting him, I don't know SOP for someone taking off like that, but high-speed chases put a lot more people at risk.
Evidence the guy “took off”? None. His hands were up and gun was stupidly pointed with finger on trigger and kid was shot. Cars now in motion from body weight at risk to public. Amazing police work. Bravo. And the other knee padding gang in blue at scene say their bro was “dragged”. Anything to justify murder. Long game for law enforcement legitimacy and rule of law? Not good, nope not at all.