A guy with a gun walks into a store.
A story that begins in this fashion can end in so many different ways. We’ve seen it all; compliance, non-compliance, armed resistance, unarmed resistance, injury, death.
In this case, a lone armed robber was having his way with 4 adult males, until one of them sees an opportunity to try and disarm him.
As soon as that happens, the window is completely open. The 3 other men jump in to take control of the situation, and the armed robber finds himself in a world of hurt.
Keeping him down and controlled; Good.
Hitting him in the head with a brick after he’s been controlled; Bad.
If the mad had still been a threat, by all means use that brick until the threat is stopped. If it’s already stopped, however, that’s where we cross boundaries that could have serious consequences.