It's wrong to bring weapons into your school.
John is parking his car in the school parking lot when he remembers that he forgot to take his handgun out of his school bag.
John wants to find a place to store the handgun.
John decides to put the handgun in his car's trunk since that would be locked all day.
John decides to bring the handgun into the school and store it in his locker until the day is done.
John gets through the school day as normal and takes the gun back home at the end of the day with no consequence.
The school's metal detector goes off and John is caught and expelled from school.