He most likely locked his knees standing at attention too long. It's not an uncommon occurrence in training. I saw one guy do it during a locker inspection and whack his head hard on a bench on the way down. The fall itself is the real danger.

I think the point is powerful people with money don't give a shit about the peasants. I don't think that's the case here, but I'm using my context clues to understand the point, given that OP used this language: "living decorations".

I think I gave you the wrong impression, I don't think that. I just thought they might have strict rules and all that and his superiors might not be so kind to him.