I don't know why I was expecting to read that Kadin would die before she got to that part. And it's gutting, given how the author talked about their bond but also how she struggled to communicate fully with him.
Sadly, I know too many people who have drowned to death. One of my two childhood best friends died that way, and the other best friend lost his younger sister in a rafting accident, when she got caught in a strainer. Reading this makes me imagine what their last minutes may have been like. It's heavy.
I've had my own instances of realizing I was in way over my head in a situation. Not quite as bad as what the author describes. To me, her situation is one where you've crossed over to the "default dead", and I have to imagine that's a whole other level of emotion than anything I've experienced.