A general had to wait

A general had to wait his turn.

Before 1793 the wounded were carried off after the battle ended.
Sometimes the next day. Napoleon's chief surgeon built a light cart on
springs with a fold-down table and drove it into the fighting instead.

Then he did the part that made officers furious: worst wound goes
first. Not the highest rank. Not even your own army. At Waterloo he
operated on the enemy with the same hands.

Two hundred years later you still sort by how bad it is.
He is the reason.