MySQL database design help

EDIT: also posted on stackoverflow: http://stackoverflow.com/questions/12148715/mysql-database-design-check-in-system

I am attempting to build a check-in system for an office building.

What happens is:

1. a Code is called about a bomb threat in building A.
2. a designated user is supposed to sweep one or more areas assigned to them.
3. a user will then check-in for their area(s) reporting on the status of the area as either not checked, checked - no problem, or checked - problem.

I will build an interface that will pull all incoming status reports.

This is the table structure I have so far:

Users
---------------
id | name | username | password

Buildings
---------------
id | name

Sections
---------------
id | building_id | name

Assignments
---------------
id | section_id | user_id

This overall design works to assign users to sections (many to many) and sections to buildings (many to one)

How do I store the status reports while being able to easily retrieve them later.

I want to be able to store status reports in a way that would allow for a user to update an answer, view old answer, and submit a new answer.

Any suggestions are greatly appreciated.