Well, if accurate then the tail breaking off would be secondary to whatever initiated it. I'll take your word for it then. This may be the case, as in the same frame I'm referring to there is a large, star-shaped dark spot on the underside of the orbiter, approx 1/2 the way back and a little left-of-center.
Trust me, this video is not of an 'artifact'. It is the shuttle and its tail falling away from it. The frame I'm referencing is approximately 2/5s thru the sequence and is quite clear. The 3 main engines are visible, it's tail is missing and there's the large dark spot on it's underside. I wrote that one off as an artifact. Perhaps some damaged heat shields and a blown tire are the cause after all with the fuel tank insulation starting the whole thing. In any event you really do have to see the frame. It's quite something. Surely someone will grab it and enhance it and you'll see what I'm talking about.
If you watch the text scrolling across the bottom of the screen, look at the phrase ". . . CAMP DAVID TO MONITOR SPACE SHUTTLE COLUMBIA SITUATION . . ."
The image you are talking about is clearest just as the second T in the word SHUTTLE appears, and before the L appears. Am I correct?