It still did not explode. Here is my best extrapolation of what he said. When there is a shuttle launch, all these people meet and decide if it should. Nearly all of them said no, they should not fly that day due to the temperature outside. They had failure of the O-rings at even higher temps. Two people walked out and actually quit.
As well, there was a huge wind shear, and that is ultimately what did in the shuttle. In cold temps, the O-rings harden, and do not stay pliable, as they should.
The O-rings started to leak, causing the flame from the srb to brake a strut, which sits at the bottom of the structure. This broken strut was forced into the tank, as they went through the wind shear{the worse wind shear a shuttle had ever experienced} This caused a hole in the tank, which just got bigger and bigger, causing it to fail and come apart.
In the transcripts they never actually say that the members of the crew were still alive, but you can deduce this by reading. My husband is pretty certain five of the seven were still alive when they hit the water.
here's a brief timeline of events{you will see it is written that there were some "explosive events" in the timeline, but ultimately the shuttle came apart, it did not explode} This is not the full transcript.
Spaceflight Now | The Challenger Accident | Timeline
I saw it as it occurred, and it sure looked like an explosion to me, but from what you're saying, the explosion was the *result* not the cause.
Andria