The story about that woman made me think of Michael Mosley. We just don't know as we get older how things like heat will affect us and climate change is making heatwaves more frequent and intense. It was, apparently, a very hot day.
The photo of that woman showed someone thin and determined looking, I can imagine her saying she would be fine. Probably there would have been a problem for the whole group regarding leaders and splitting the group if someone accompanied her back. they could have messaged the ship to let them know of course.
It's the shenanigans of the family that get me, she was old, she was on a trip, quite possibly her death was painless and over quickly. Better than a long, painful death in a care home!