The sweep of sudden good behaviour that settles over a class when a routine session of pre-teacher misbehaviour goes horribly wrong. Within seconds, everyone will be sat, books turned to the correct pages, in absolute silence.
A good example being when a game of indoor football knocks a cup of full coffee onto the fifth years' coursework.
Time stopped, the camera swept around the football, there was an extreme close-up on a droplet of coffee, and every child lifted into the air, and flew back into their seats.
The teacher, when he arrived, would see two things; the culmination of the fifth years' secondary education rendered useless, and a class of 30 really well behaved twelve year olds.
We thought the two things would pretty much balance out.