What upsets the teachers at beginning of chapter 5 in A Separate Peace?

At the beginning of chapter 5 in A Separate Peace, the teachers are upset by the vandalism of the Devon School campus. During a weekend break, several students from another school, presumably Devon, came onto the campus and caused damage to various properties, including the sports equipment and the gymnasium. This act of vandalism not only disrupts the school environment but also creates tension and animosity between the students of the two schools.