From the article:
When a submarine hull collapses, it moves inward at about 1,500mph (2,414km/h) - that’s 2,200ft (671m) per second, says Dave Corley, a former US nuclear submarine officer.
The time required for complete collapse is about one millisecond, or one thousandth of a second.
A human brain responds instinctually to a stimulus at about 25 milliseconds, Mr Corley says. Human rational response - from sensing to acting - is believed to be at best 150 milliseconds.
The air inside a sub has a fairly high concentration of hydrocarbon vapours.
When the hull collapses, the air auto-ignites and an explosion follows the initial rapid implosion, Mr Corley says.
Human bodies incinerate and are turned to ash and dust instantly.
There have been credible reports that they had initiated an emergency ascent, though I am not sure if this is a certainty. If it’s true, they were definitely aware that they were in serious danger long enough to make and enact that decision.