Amazing video.
Sorry, I think there's confusion between detatching the slide (using the detatchment point on the door sill after inflation) as opposed to taking the actual (uninflated) slide pack out of its bustle from inside the aircraft with the door closed. That discussion branched off as I had never heard of this being taught before...
With regard to pax in the water- had they been IN the water, or fo a long period of time, cabin crew are taught to get survivors into a huddle, using the heat escape lessening position (HELP) which involves bringing the extremeties up to contain body heat, also having everyone facing inwards with the legs up means that the group can support injured/unconscious pax or those without lifejackets...
Jet II- I was under the impression the rear doors weren't opened, I'm more familiar with the big sister of the 320- does the 320 indeed have off-wing slides? The one pictured seem to have orange markers as do the Boeing off-wing slides...