Thinking about how we treat head stomp as this pivotal moment of Descent Into Darkness(™) character development, but honestly Silver had no choice. What else could he possibly have done?
Consider that this crew made Dufresne go over the side. [Now that is dumb. It is a dumb plot device. You should not make your accountant fight. But here we are, text is text.]
Consider Silver saying: “We’ve been assigned responsibility for raids we were nowhere near. Jesus, I’ve been given credit for having been a part of some of them. They are so terrified of you, they’re terrified of me.”
Silver has, for months, been staying on the ship while Flint goes off for some light wholesale slaughter. Silver has a fantastic reason not to fight, and no one could possibly expect him to. Flint’s reputation encompasses them both, and together they have a mystique—he can get by on that, and the presumption that if he could go fight, well of course he would.
Except he knows he wouldn’t have. And Flint knows he wouldn’t have. In a certain, horrible sense he is very lucky to have lost his leg and avoided the whole question, but it must haunt him, especially with every one of Flint’s comments about weakness and pretenders.
Now he is going ashore with the express purpose of creating fear, while Flint stays on the ship. (Arguably this is mostly what Flint was doing during the raids as well.) Dufresne challenges him. Specifically Dufresne, given the above history. I don’t see any way for that to play out where both Silver doesn’t lose face and Dufresne lives. Flint could have left him alive, because no one would ever doubt his capacity for violence. But Silver can’t. He has to kill him.
So if you have to kill someone, and the only choice is how, might as well do it in a way that makes an impression. Silver obviously understands the power of stories as well as anyone, and what the impact will be. None of this is to say he didn’t also totally lose his shit, or that he isn’t fucked up after, or that it’s not the most epic disability rage because it is. It can be all that, but it was also the totally rational choice in the situation, and being who he is I don’t think he was unaware of that.