Final answer:
The reason he could not feel his feet when soaking them in extremely hot water is because the water was too hot. The contrast between the high temperature of the water and the extreme cold outside can cause the nerves in the feet to stop functioning properly, leading to the loss of sensation.
Step-by-step explanation:
The reason he could not feel his feet when soaking them in extremely hot water is because the water was too hot. When the water is too hot, it can cause damage to the nerves in the feet, leading to numbness or loss of sensation. This is similar to how extreme temperatures can cause burns or frostbite on the skin.
In this case, the character in the passage was soaking his feet in extremely hot water in freezing temperatures. The contrast between the high temperature of the water and the extreme cold outside can cause the nerves in the feet to stop functioning properly, leading to the loss of sensation. This is why he could not feel his feet when they were in the hot water.