That's a good, interesting question to which there is not an easy answer because evolution as well as technological evolution can take different paths in isolation. Even with the absence of other technology in the 1920s it would be extremely hard to envision a time when people from all 4 corners of the world could partake in a business conference in which they can see each other without any of them having to leave the country they were in would would be more probable is that people would look at the wonder invention of the time, the airplane and imagine one so fast that they could travel across the globe in seconds, while flying machines today can do that or are at least we are on the verge, we are not all traveling around the world in seconds we tend to favour the internet. So what's not there influences what is there. Because we are the way we are we compare things to ourselves we look at the unknown and treat it like it's the known until we learn otherwise, for example you had never seen a wolf before and were completely unaware of them and all other animals, when you saw a wolf you would see it has two eyes like you so you would assume on that basis it could see, then you would see it's 'hands' and conclude that they are very different to yours, then you might witness it licking it's own bum which you can't do and would imagine wouldn't want to do and you definitely don't need to do because you evolved hands and arms which allow to clean yourself without having to use your tongue and eventually you would realize this distinction between your approach to hygiene and a wolf's.
But back to the initial question there could be any number of ways of performing surgery when developed from a different starting point. For example maybe an alien species could perform surgery with just a superior sense of touch to us, where they could feel pressure and other factors far better than we can. I had to have an operation on one of my middle fingers due to an infection, after the pain, swelling etc had subsided, for a little while I had a super sensitive finger which meant I was able to touch surfaces of things that I considered smooth and find out they were not as smooth as I previously thought, my own skin is one example.
With regards to the the camouflage question, camouflage is only effective if it's in the correct environment, for example there is a fish in Venezuela I forget it's name but it has mirrored scales which means its as good as invisible (you can see it's shadow however which makes spear fishing possible though very tricky) the colours and objects are distorted by the water so this plays into the fishes advantage if it was on the ground out of water it would be more conspicuous. If a person was covered in mirrors in one of those Hall of Mirrors things you get at funfairs, that would be an excellent camouflage because you would only ever see yourself in all sorts of distorted ways. Imagine the same person stood in the middle of an art gallery the person would be very noticeable as they would be were all the pictures seem to converge into one mixed up image (unless you were in a gallery full of Picasso pieces in which case you wouldn't notice)