Hindsight bias
In accident investigation there is a notion known as the "hindsight bias". This is the understandable inclination to say (of those involved): "Why did they do this?" or "why didn't they do that?" etc.
While an accident is evolving - all the holes are lining up - those involved do not appreciate they are involved and often take the "best" steps to resolve the situation, often falling back to "knowledge-based" rules.
Virtually every accident comprises a sequence of events; each sequence is an "opportunity" to prevent the accident - assuming you know the accident is happening.