Plot hole: There is no possible way for the chubby mayor to be able to get in Flint's lab. There is no side entry, and the space other characters use to get in is too tight for him.
Plot hole: When Flint gets to his lab to shut down the machine he finds the mayor there inputting more food. The mayor says he's been ordering food for ten minutes, how is this possible when he was just there with Flint on the stage barely a minute or so before? Also, how did the mayor manage to get his large self back to Flint's lab so quickly?