After teasing the lion with his car for a bit, the lion stops, stares at the man and lets out the tiniest, yet powerful roar. While the lion's actions were small, it was enough to freak out the man. He quickly rolled up his window and let out a shriek that seems to say, "OMG I'm I almost just died."
Seriously, turn your sound up, it's worth a listen.
While observing a lion in the wild is fine, stalking it with your car with your window down is a terrible idea.