Michael backs up the charger so the car's windshield is parallel to the shooter and thus impossible for the shooter to hit. About a quarter of a second later his windshield takes a direct hit in the middle which causes glass micro-fragments to fly into the interior. This indicates the shot came from the front. The basis of this goof is inconsistent car positions.
Michael is posing as a former green beret, a special forces branch of the US Army. When he talks to Kent he closes the conversation with "semper fi" a US marines phrase not army, but at the start of the conversation Kent is identified as a former marine, so it makes perfect sense that Michael would say "semper fi" to him.