Congratulations. You will be a good Doctor. You have reflected , shared and sought guidance. I have trained medical Students and latterly Postgraduate Doctors for over 20 years. Welcome to the ranks of those who have experienced"event stress" or "combat paralysis". Follow your first post with "what should I have done?" add a third of " How will I perform differently should the circumstance occur again?" and you are well on the track that the qualified and alledgedly wiser follow on a daily basis. the only "rules" I have found helpful are:- "Never make the same mistake twice" "Be honest with yourself and colleagues"- it looks like you will be able to follow both.

I think that it is very hard to do 'something' when faced with a situation you are not expecting.
I remember being on a tram in Athens when a boy passed out (presumably it was just too hot an he had not drank enough) and did not know if I should intervene or not as I could not speak any Greek past hello and thank you. Luckily the other Greek passengers knew what to do and the boy recovered well but I remember feeling mortification that I felt unable to do anything, mainly due to the language barrier.
In some ways medicine is like learning a language, and over time you learn it, and some people pick it up and feel more confident using it quicker than others. I wasn't the quickest or most confident but I got there in the end and you will too.