I went crabbing and the resources I found said that killing them before cooking them was likely more humane than boiling them alive, so that’s what I did.
My old neighbor’s cat once left a paralyzed/twitching rat outside my door, which I found in the morning. I quickly realized that the rat was not going to recover (it had already been there for hours), so I had to figure out a way to quickly end its suffering. I did not eat the rat though.