First off, I'll say that I'm not a reader of short fiction, so I don't know exactly how things ought to be done in that field.
POV
I have a strong bias against omniscient that I often find confusing for the reader. In this piece, you present an omniscient POV where essentially there is a jump of focus each time there is a dialog (example, camera is on character A. Dialog happens between character A and character B, camera is on character B, ...). I found that pattern to be disturbing in a sense that it did not allow me to know which character this story was about (up until the very end of the
story). I think that the use of a single POV character would have been much better, allowing me to care for the characters.
Story
In this piece, I didn't have much in the way of motivation for the characters : I didn't understand why the character suddenly decided to tear his wall down for instance. I would have liked more insight into the characters
Also, the end felt rushed (we don't even get to see the death of the character), and is a case of "Deus in machina" in action. It would have been better to have some foreshadowing that things would get very bad for the little girl in the case she went out : it would have brought both tension in the middle of the story, and a more satisfying resolution (instead of having to be told that all was well in the end because ...)
Writing
At times, there is way too much detail (the "bottom thumb knuckles" for instance, where just "knuckles" would have been enough), and in a way, some parts felt like a commercial (I don't need to know the make and model of the motorcycle). Also, telling me the number of the bus line not once, but twice was at least one time too much, and citing the issue of the comics books shouldn't happen every time you speak about the book. Try to revise to eliminate those unnecessary words.
Conclusion
Make it clear from the beginning which character this story is about, introduce tension through foreshadowing, show us more motivation in the characters, and revise the language to be tighter and you should have a much stronger story.
Anyway, nice try for a first time, keep practising!