By the looks of this, this sounds like a pretty sound method then. I won't necessarily CTB but if I do I think I will do this. It'll be a bit traumatising for the people who see it but I don't think too much. I'd just have to pray there are no good samaritans that jump in after me, if I were to live and them to die would be absolutely horrible, or for us to both die would just be tragic.
Other than that im a reasonable swimmer so I feel like I would pass out from the cold and then drown, and im fine with that. Jumping would be the hard part but even with SI I don't think id have much chance unless the lifeboats were coincidentally quick.