To go to school at night and sleep during the day would be a much different experience than the majority of students have experienced. Doing school at night would lead to a much quieter work environment because the majority of people would be asleep. This might be nice, but, because you would be sleeping all day you wouldn't be a real part of society. Students wouldn't see people or get Vitamin D from the sun. If they go to in-person school at night, the only people they would see is classmates and teachers. There wouldn't be much of a social life for them. Once a student is done with their classes, it will be morning and all common hang-out places will be closed.
According to how the narrative is made, specifically how he tells us what he's done and his situation, it can be intuited that he was struggling in that time and needed to eat, so he had to steal some food but he was planning to return it as soon as possible.
