Grabbed the nine-ball, opened up the door, then got in
Kendrick grabbed himself a 9 mm handgun, ran out the door and into a waiting car. Also alludes to the pool game 9-ball where the lowest numbered ball on the table is hit into the pocket.
In the game Nine-ball the 9 must be hit into the pocket after every other ball has been hit. What Kendrick was about to do with his “9 ball” would have ended the game right away. It has a finality to it and it could have backfired on him, much like it does in the billiards game where hitting the 9 in first would be a disqualification, if the other group of people also had a gun (probable since they were gang members). His friends tell him to calm down and let the process happen before he does something he will regret.
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