Coffman,
we did indeed have at least one liferaft escape from the stowage in flight but not I think with quite so dramatic consequences.
I have mentioned in an earlier post that the UK sourced liferafts in the 'K' were larger (MS26 and then MS 33 in the stretched version) than those fitted to US a/c. They were a real headache for the technicians to fit as smudge confirmed. I also recalled seeing two demos of the MS33 where the liferafts merely lay on the wing blowing like beached whales.
When our 'K' model was first stretched the MS 33 was not ready so for large pax loads we carried an MS 9 which was supposed to be launched out through the cargo compartment aft escape hatch. It was not exactly a light item but I suppose in extremis the adreniline would turbo charge the muscles !