This question is asking about two different things. The rats escape in October, and Holling's cream puff disaster also happens in October. The events are separate, and I will focus on some of the results of the cream puff accident.
Mrs. Baker asks Holling to carry the trays of cream puffs to her room. She then gives Holling a box of chalkboard erasers to pound out. He pounds them out, but the wind carries the chalk dust up to the open windows where the puffs are placed. The dust lands on all of the cream puffs. Holling has a choice at this point. Say something about it or not. Holling chooses to not mention that the cream puffs are tainted with chalk dust, and Mrs. Baker gives Holling a puff for his good work with the erasers. Soon after, all of the ladies that the cream puffs go to nearly choke to death on the chalked up puffs. Holling's friends discover that Holling received a cream puff, and they are upset that they did not. They demand that Holling gets them a cream puff.
Holling now has to figure out how to get his classmates a cream puff. He doesn't have enough money to buy them, so he offers to work for the baker as payment. The baker says that he doesn't need help. He needs somebody that knows Shakespeare. By this point in the story, Holling has been deep into Shakespeare with Mrs. Baker, and he astounds the baker with his knowledge. The baker gives Holling some cream puffs because Holling proved his knowledge and agreed to be a part of the upcoming Shakespeare performance. Unfortunately, the escaped rats eat the cream puffs during recess, and the class is still angry at Holling. Another unfortunate result of the cream puffs is that Holling must wear a terribly embarrassing costume for his Shakespeare performance. All of the above could have been avoided had Holling not clapped out those erasers where he did.