Crocodile attack video.

[KrokadilyanGuy3]

Asides from what Chuck has already said. Crocodiles attack from the side, where they can see. The man putting in his hand was showing you crocodiles cannot see in that general location. Actually, he probably wasn't showing you that, but that is the true reason to why he did it. Much like people putting their heads into alligator mouths. Good thing that wasn't his trick...
Zane

[Rikki]

People do stupid things, hope the crocks ok.....

[Cruciform]

It was definitely dumb, but none of us really know what led up to it.

Chuck and Zane have made a couple of intelligent observations on what he might have been showing the audience.

We also don't know if he was the regular trainer, experienced, or new. For all we know it was his first week at the job, and he was just repeating what he had seen others do successfully.

The bite trigger is a good theory as to why it snapped. I saw an example of it in action on one of the Croc Week specials. Just like a mousetrap, supersized.