Mrs McLaren feels it's a fuss over nothing. Bigger pupils always chase the younger ones out of the shed. Mrs McLaren is annoyed when the headteacher speaks to the class and tells them to report any bullying directly to her. Personal definitions of bullying differ. The P5 pupils think they are in trouble for playing in the shed when their teacher told them not to, and are too frightened to speak out.
Nobody speaks out.
A number of things went wrong in this school.