Screams for help could be heard from the St Kevin's College campus in Oamaru yesterday.
But the pupils screaming were merely acting for the benefit of the largest multi-agency emergency services exercise staged in Oamaru.
Senior Sergeant Jason McCoy, of Oamaru, said the exercise was a ''response to mass casualties'' after an unspecified event.
''We've got civil defence with a welfare centre for all those other kids.''
He said 24 local police officers took part, and eight officers from Dunedin oversaw the exercise.
Of importance was the time it took to set up a treatment and triage area, and how well the team slipped into its management structure and environment.
It was four minutes from the arrival at the scene until the St John crew sent their first detailed situation report ''which is exceptional''.
Pupils wanted ''insight into how they might be able to help respond effectively'' in an emergency situation.