One summer I was up in Peekskill NY. It was a very hot day, a friend and I went to this creek that is extremely cold in one spot. I went in. It was freezing. As I was in the water, I tried to acclimatize to it. It felt being warm and cold at the same time. I must have been in the water for about 15 mins and had no intentions of coming out. It's as if I wanted to conquer the feeling of being cold. I wasn't aware that I was mentally lowering my body temperature.
All of a sudden I hear my friend yelling at me to come out of the water. He sounded urgent. I thought that maybe the cops were arriving because I was in a fishing area. So I reluctantly came out. My friend told me that I was turning blue, it scared him.
If it weren't for him, I would have stayed in the water much longer. It took me a long time to defrost, get the chills out.
One can never assume what one would do when in extremely cold water. The mind works differently. I was very surprised how irrational I was. At least I could have walked to shore, while the three that lost their lives, couldn't. :(
I have fished that area and futher north, plus the Delware river in spring trout season. I wore waders, two pair of pants and longjohns and all I could take was about fifteen minutes in that fast moving cold water. I would walk the bank fishing and looking likely holes for an hour before venturing back into the water.