Perhaps there was more to this than was shown on UK TV. I saw the incident on (I think) a German channel. The sequence of events which does not seem to be described above was like this.
Dauphin hovering over water at 20 - 30 feet, swimmer in the door apparently waiting to abseil down a rope, but the rope had turned into a bunch of bastards and no 2 crewie was trying to unravel the hopeless mess.
Cut to shot of helo with said crew still in the door plop firmly into the ogwash on a level keel with no yaw apparent and a bit tail down - the fenestron was half submerged for a second or so, water almost at cabin floor level.
Helo immediately and abruptly pulls up out of water, I looked but could see no sign of fenestron blades either present or absent. Helo immediately began to yaw, after 2 turns or so swimmer has had enough and jumps, a second or so later pilot decides hes had enough too and ditches, clearly on top of swimmer. Two pwople seen scrambling clear of cabin as it sinks.
It looked to me like an inadvertent ditching which wrecked the fenestron with end result inevitable after lifting off again.
I can just picture the pilot looking over his shoulder in frustration to see what the crew were up to and let it just sink down into the river, then Oh **** O Dear and pull up by reflex. Look over your left shoulder and which way does the collective move???
