I wouldn't get your mate to jump out, unless you're after some life insurance money or something
I would try and find (or have ready before the flight) the frequency of the ops room on the rig. I dunno if they monitor 121.5, though I suspect they do. They could possibly pass wind and sea information to you if you had time, they also have fast rescue craft onboard so try and ditch near the rig if possible. You could always checkout
weather buoys before the flight to give an idea of what to expect if the worse happens.
I would crack the door open, incase the fusalage becomes distorted in the ditching. Better to have the door fly open that get stuck. The arguement could be that this will reduce the strength of the cockpit, but judging by the flimsiness of light aircraft, I don't think this will be an issue (give me a composite A/C with a 25g impact cockpit shell any day
).....
EA