Yeah, a guy at work used to bring some in after he caught and killed his own.
From what he was telling me, it takes a long time for a turtle to figure out that it is dead. The muscles will try to move for hours and hours after being separated from the rest of the body. He would kill them by decapitating them, then do a real rough cleaning by spliting open the the shell and scooping out the innards, then throw the whole thing in a bag in the freezer until the next day when he felt like could cut it up without it squirming all over the place.
I guess hilarity can really ensue by asking your wife to make some soup from some freshly killed and cleaned meat.
That is according to my friend.