In the movie Hunt for Red October - Sean Connery, the Soviet sub commander, is faced with a critical decision when a torpedo is fired at his sub; follow the check-list procedure or pause. He decides to delay action as the torpedo closes on his ship. A few seconds before impact he orders the sub to turn, the torpedo misses. A critical moment in the battle. He broke-set.
Connery did what fast teams do, they break-set frequently. Had he followed the check list the torpedo would have hit his ship. Teams do this also, they move in lock-step, following process/procedures and fall off a cliff, as a group!
On the other hand, we observed fast teams frequently breaking-set in order to stay alert and make incremental adjustments to hit their target. They broke-set before the project slipped and before they had a crisis. They created change. Typically teams reduce change and when they have to break-set they have to make large course corrections, which takes time. Further, teams that tried to execute to their plan, more times than not, had overruns. When you try to follow a plan you typically miss it, but break-plan and pull-in and your chances of success increase.
An Israeli General once commented, "A plan is only a common base for change."