Teres

Yes, I would expect this "last patch" to be relatively far away from the others and thus easy to miss. He would also be standing on dry ground with one foot and he is not going very fast. It would be possible, but it is quite contrived and not at all necessary.

With such a catastrophic wound you'd think he should have had a much more severe fall than merely tripping over.

And, eventually, Axis will even throw him in prison!

Correct. Because he just can't bring himself to have the guy killed on the spot.
Immediately before making this decision he has a different character... not killed on the spot, but dragged away to be slowly tortured to death. Without a trial. Axis doesn't believe in due process. People get punished according to his arbitrary whims of the moment.