Two possibilities:
1. They had some form of relationship and out of all other possible arrangements, he just happened to have an apartment directly above hers.
2. She didn't know him and really did go to the wrong floor by mistake and entered his apartment because it was directly above hers.
#1 is very unlikely
#2 is the more simple and likely explanation, particularly if she was impaired in some way.
Two possibilities:
1. They had some form of relationship and out of all other possible arrangements, he just happened to have an apartment directly above hers.
2. She didn’t know him and really did go to the wrong floor by mistake and entered his apartment because it was directly above hers.
#1 is very unlikely
#2 is the more simple and likely explanation, particularly if she was impaired in some way.
Third Possibility-—His apartment is directly above hers. He was playing his music too loud. She was tired. She gets mad. She goes to his apartment. They have words. She shoots him.