Formatting issues aside, the story idea doesn't really lead anywhere. The addict awakens from a dream and finds himself hallucinating about his next fix before he dies. While I see where you want to go with the idea, it kind of gets stuck in the middle. The reveal doesn't have a lot of emotional impact. Mahdy has a good point in that you have a lot of action statements that basically say the same thing repeatedly--he keeps cleaning.
What is the emotional tone you want for the piece? Based on that subjective piece, what might the viewer see (the objective piece)? My guess is that you want the man to feel guilt or remorse. So in the end of the story, the man has to resolve the guilt. Death is not a resolution for the viewer. As a result, this ending fails to work for me. Have him resolve his guilt, then die. Though, I don't think he would.
While it's okay to ask the audience to suspend belief, for him to die at the end doesn't seem very realistic. Abstinence from alcohol for a chronic alcoholic can lead to life threatening withdrawal symptoms. But for an injectible drug like heroin, the symptoms feel horrible but don't pose as much threat. Meth, a
stimulant, is also injectable but usually acute withdrawal is sleepiness followed by insomnia. In both cases, an overdose is more deadly than five days of abstinence.
Break up the action by giving us more depth to his struggle. Have the child and woman pop up as he's cleaning. How does he react? You could have the woman talking to him, though he is unaware of her.
As he shares some of his story, she is feeding back some of his feelings. Perhaps as part of the ghostly aspect, have him glance up and she's not there. Have him cleaning and see the boy. He pursues the boy only to find the hallway empty. In other words, help the audience to learn about how the addiction affects his life. Even if he justs talks to himself as he works. In the end, he needs to confront these urges to use vs. his desire to abstain. Have him proud, maybe defend his abstinance. Then raise the stakes.
As he cowers at the end, have a locker open. There is a loaded syringe inside. The syringe monster is on one side, his son advances on the other calling to this father. Pull back with him having to choose one or the other. I might have it end with him curled in the middle of the floor weeping as the bell rings. Or maybe dead with the syringe in his hand and belt around his arm.
The important part of the story is in exposing what's happening inside him--his struggle with his addiction. You can bring it to a positive or negative conclusion. You can only leave it unresolved if you have made his emotional conflict evident in the story. The current screenplay doesn't do that for me. It only shows a janitor frustrated with an uncleanable hallway. Subtle is often far more powerful than in-the-face imagery.
I like the plot. I think to make it a story, you need to develop the character's struggle more.