... ... I am not sure how these secure to the bars, but I was wondering if it possible to somehow loosen them up a bit, so if the bike does fall, they will pop off rather than break. ... ...
I think you want them to be tight. If they are loose, they may turn side to side while you are shifting them.
I was concerned about damage if my bike falls over, I have normal drop bars, not the ones you are talking about. I aimed the levers on mine slightly inwards, not straight down thinking that they would be better protected that way. But from the scuff marks on my levers, they still have hit the ground when the bike fell over or when I had a bad crash.
On my last tour, I put a piece of short pipe insulation around my top tube with a velcro strap to hold it in place. If my bars turn all the way to the side so that my bar end shifter hits the top tube, the insulation protects the top tube from getting dented. If I lean my bike against a pole or something like than, the pipe insulation also protects the top tube paint.
Bar end shifters were used by tourists before brifters were invented. It was a way to keep your hands on the bars while shifting which can be handy with a loaded slow moving bike, downtube levers (and later stem mounted shifters) were the only other option but you had to take a hand off the bars to shift with those. I started using bar end shifters in the mid 1970s.