To me, the four most important events in this story are these:
- Tom decides to stay home instead of going out with his wife. This is our first sign as to how dedicated he is to his work.
- The piece of paper flies out the window. This sets up the major conflict in the story.
- Tom goes out on the ledge to get it and almost dies. This is the main action of the story where Tom fights against his fear and against the events that make it hard for him to get the paper and get back in.
- The paper flies back out the window and Tom laughs. This shows us the moral of the story -- it shows us that Tom has changed his attitudes and no longer thinks his work is the most important thing.