In the first few drafts, only the characters themselves shrank, and all of the action took place in this one lab room. When I decided to change the method of shrinking, the fact that the building itself would also be affected allowed the action to play out on two levels: the second floor lab and the first floor records room. That made it much easier to prevent the “big” characters from helping the “little” characters, so we could watch Flint and company fend for themselves and make the story much more interesting.