Sorry, Nick, I am pretty sure the horn goes off as the camera goes round, not the helo - i.e. the gyro on the camera can't keep up with the spinning of the helo. My reading is as follows (in this order) :
1/ Something starts to make the helo spin
2/ The camera continues to point in the same direction because it is stabilized
3/ The skid passed through the camera view
4/ After a second or so the horn goes off
John