Snipped for focus
This reminds of something in my life. I’ll keep the details vague.
Some years ago, I was in a life-threatening natural disaster. I had walked already, a considerable distance, and then, after a considerable amount of mental and physical stress, I decided I needed to move to a safer place—about 15 feet away. I picked up my laptop computer, lightweight, in a light carrying case, having lots of things on it I wanted to keep. I took one step, and decided that it was too much of a burden; I set it down and moved on. It was destroyed; I survived, and to this day, I’m not sure if my decision was a realistic evaluation of the situation, or a result of my state of mental confusion.
So, you see where I’m going with this. I find it very believable that he might have carried his backpack for a while and then simply abandoned it.