the gears sank in, folded backwards and the aircraft fell on its belly, breaking into three pieces as it dug in.
Hmm. I'd put money on the aircraft 'cracking up'
before the RTO. The bangs heard by the crew could well have been some pretty significant structures letting loose. I can't see a structurally sound airframe breaking up, as this did, from the roughest of (fairly) low speed over-runs.