'"The danger here is slipping, hitting my head, becoming unconscious, ….."
How would having a partner mitigate that risk?'
I can think of a few potential ways:
1) I start to fall, partner grabs me and saves me from falling and hitting my head, becoming unconsious, etc. I have been grabbed as I started to fall – PROBABLY it would not have been a serious fall, but there are always those freak accidents. Admittedly, the possibility of a companion actually preventing the serious injury is slim, but it exists.
2) I start to do something and my partner sees what I do not, that I am doing something that will potentially cause a fall, and tells me so, thereby averting my falling, hitting my head, etc.
2) I fall, become unconscious, my partner assesses the situation and summons assistance (via electronic device, or just by running for the nearest place to summon help), and I am airlifted out in time…versus I fall, remain unconscious and die of dehydration/hypothermia/cerebral swelling/take your pick and am found a few days later (dead) by the next person along the trail, or I fall down a slope off the trail and am found (or not) months later by some unlucky person.