~25 are more than enough, if they are willing to die. Once a single person gets on the gorillas back while it is distracted and does a proper rear-naked-choke its gg.
Edit: Even if you think this is bs, there is no fucking way a gorilla could take 100. People are vastly overestimating how strong the average gorilla is and underestimating how strong a human pumped full of adrenaline is.
100%. A good comparison is 100 rats vs 1 human. And a human is much closer in strength to a gorilla than to a rat.