You are correct. Brain injury is very often leads to violent and irrational behavior. This behavior of a stunned, injured motorist can lead to a field execution by a cowardly cop who has no desire to sort things out. Much easier to just start shooting. Safer for the cop who just wants to preserve his own skin and his gubment cheese fueled lifestyle.
Cops have forgotten that hazarding their lives to protect innocents is part of the job. Instead, they resort to maximum force the moment their lives are at risk.
There was a swat case where a woman and girl were held into custody while their home was searched. The holding officer shot the dog. (you knew that was coming). Another officer paniced and sprayed the wall, killing one and wounding the other. There were no consequences because he was “into fear for his life”