There was a famous search and rescue in the winter years ago. I was involved with SAR and wilderness medicine back then and it wound up it was actually a neighbor and became a friend with this person. He was a nice person and we wound up talking about the event. He/she did not wind up unscathed from the event during his cross country ski trip. He/she lost some limbs to frostbite, He/she had a dog with him/her. It was a Husky or Malamute, some kind of mix. A real winter dog. He/she had to carry the dog over at least one of the streams because the dog wouldn't cross it. So his/her lower extremities got wet. The interesting part was my mother in law had a picture in her mind that the dog stayed with him/her and saved that persons life with its body heat, literally. Talking with him/her, He told me that once he/she started violently shaking from hypothermia, the dog got up and left him to sleep several feet away to not put up with his masters shaking. He/she loved that dog, even after he got home but my MIL no longer thought very much of it. Anyway, don't be so sure what your dog will or wouldn't do. This one wouldn't even keep its master warm if it meant no sleep.