I greatly enjoyed reading this story. As someone who is unfamiliar with GDF, I didnt feel lost any point as I read about the characters, gangs, and locations. The setting and situation were presented quickly but without the feeling of an exposition dump, weaving into the situation nicely.
As mentioned in another comment, the ending felt abrupt. Possibly some of the initial detail on how the plan had gone awry could have been sacrificed for the word count at the end, but the story's initual pacing would have suffered as a result. Such is the challenge of a one page story.
Regardless of the one critique, the overall result is well executed and a great read. Bravo!