Yes, he was Muslim and Pakistani, don't think it's relevant though, but time will tell. From witness reports on the news broadcasts, seems he was very comfortable with the gun. Efficient changing clips, body position etc. but then again how versed the average person is on that, who knows.
Here's a question. You are standing there on the street with your helmet in hand and someone starts to shoot. They are facing away from you and maybe 10-15 feet away. The shooter starts walking away from you. What do you do?
In hindsight, I think I'd batter the person's arm and then their head with my helmet. In the moment...I'd probably run.