Clarification needed - Run in with Tom Pettigrew after shooting her brother 

According to the Wiki article, under "Brother's shooting": "...later pointing the weapon at a moving vehicle on the adjacent road, trying to get into the vehicle...."

Does the above have anything to do with this?  It doesn't seem so to me.  Here's a snippet of the article:

Carrying a shotgun by her side, a 21-year-old Bishop walked intently across a car lot into the adjacent storefront, where she began searching for car keys. Coming down from the second floor, she was heading toward the garage when she ran into Tom Pettigrew and a friend, who had spotted her in the parking lot and came to investigate.  "Her gun hit me in the chest," Pettigrew, 45, recalled from his Quincy apartment. "I yelled, 'What are you doing?' and she screamed at me to put my hands up. So I put my hands up."

But the Braintree police chief has cast doubt on that conclusion [that she accidentally killed her brother], and the armed confrontation at the garage provides new insight into her state of mind after her brother's death. The Boston Herald first reported Pettigrew's account of the events today.  Only minutes after that shooting, according to Pettigrew, Bishop frantically told workers at the garage she had been in an argument with her husband and needed a car to escape, nervously scanning the premises as she kept the gun pointed at their backs.

So, my question is did this Pettigrew incident happen before or after she pointed the weapon at a moving vehicle?  In other words, what's the time line?  Thanks.