Taking my script idea as the basis for this discussion, I’d present my breakdown as follows:
The inciting incident is when the (as-yet unnamed) other customer mistakenly believes Michael has a gun.
The first act climax comes when Michael deliberately locks the door of the store, so actually making a move that could be considered taking the store hostage.
The first act climax sets up the second act, in that the entirety of the second act consists of the apparent hostage situation, and how it plays out.
The main turning points are:
- The Customer mistakenly thinking Michael has a gun
- Michael taking the store ‘hostage’
- John knocking Michael out
- John finding Michael’s note
- The police arriving at the scene
- Michael telling Kristi about his undying love
- Michael ‘being a man’ and turning the tables on John
- Kristi and Michael together
The film is resolved in the third act with the police arriving and Michael finally standing up for himself, and actually placing the blame for the whole situation on John.
Michael gets what he wants (Kristi), but also gets what he needs (self-confidence, and standing up for himself).