@izzythepush,
Weighing up which patients are to be saved in critical situations is actually a decision that lies outside the medical profession (saving lives).
As an aside: my father told me a story from WWII, when the German army was pushed back by Russian troops.
My father studied medicine during that time, but he was also a medic in the tank troops (2nd Medical Company 57) for several months every year (in Russia as a sergeant).
The unit's "advanced dressing station" was in a wing of a large orthodox monastery, my father being the only "doctor" (having studied 6 trimesters [= two years] medicine at that time). Russians troops entered the monastery on the opposite side.
So he had to decide who he would take with his few people - and only five light armoured halftracks left - who he would take with him. He decided on the nine most seriously wounded soldiers.
When they arrived after some days at a field hospital, a military police general asked him, where he had the 5,000 blankets from mentioned advanced dressing station ...
I've got the letters my father wrote in those days to his girl friend (later wife, my mother). He had had very big conscience problems that he had to leave the others behind.