And when it does happen, the clock does not reset.
This is something operational managers who demand reliability standards of "many nines, five" fail to realise. When the system at 99.995 fails at 0200 in the air traffic centre it is the worst 26.5 minutes of the controllers long career of shifts.
In sympathising with the poor lad or lass after rectification, the manager must remember that tomorrow night the same thing can happen - and the reliability standard is still 99.995!
MJG
Been there done that - both Australian centers some years ago.
P.S. Some posters should be careful in selectively "remembering" discussions in the GIT in the 1990's. Some of us still have the minutes and papers on file.