There was too much time between the 5 and 3 shots. Driver would have had his weapon at the ready. I think driver responded to Garrett's threatening him with weapon, as can be seen in that still photo with G's arm raised and cocked at the elbow. Sufficient grounds for defensive action by driver IMO.
So the FBI had the information during the impeachment? Trump was impeached for asking Ukraine to look into these allegations and they turn out to be true?