Watching again, it does seem that he sped up after he got hit. Someone would have to frame-by-frame it and use Google Street View to determine his rate of speed and acceleration.
“it does seem that he sped up after he got hit”
Correlation is not causation. His path is directly towards the crowded street. He never deviates from his path.
I’m guessing something happened just before we see him continue down the road, like those others chasing him might have hit his car or whatever. He got scared and he had nowhere to go. Putting the car in reverse means stopping, shifting and going back into a dangerous situation. Yes, it looks like he speeds up, probably he thinks he is trying to save his life and this is the only way. Like many of us he probably saw other riot situations where cars were surrounded and people dragged out and beaten and he already knew what he was going to do in that situation, that he unfortunately found himself in. Did he get lost, make a wrong turn? Did he have a confederate flag sticker or something similar on his car and that caused the initial contact against him by the crowd? Maybe.