"taking everything into consideration, common sense should have prevailed here"
And that's the main problem, in a case of sudden emergency or possibly risk of life, common sense usually comes second place. Its only after the event the scene becomes a reality.
I don't know if you can recall the incident about two years ago, when either two police officer's or PCSO's were instructed not to try a rescue of someone drowning. That brought headline news, and I bet that the people involved still to this day have deeply regretted that event.
How many times do your hear about people going into an house on fire, so as to do a rescue attempt, especially if children are possibly involved?.
Usually after those type of attempts, the same is possibly stated "anybody would have done the same"?.