Scary stuff. He's lucky he's alive. Good job on his part!
Speaking of shoving an arm down the animals throat; There's a mane nick-named the "father of modern taxidermy" (Carl Akeley). He mounted a number of specimens in the Field Museum (Chicago) and elsewhere.
Anyway, he was attacked by a Jaguar. He too shoved his arm down the beasts throat, hence killing the Jaguar with his bare hands. Here's a photo of him with the Jaguar. Carl got banged up but survived the attack.