a smash like that doesn't always bleed right away, I wouldn't expect gushing blood. I been smashed by stuff (not a bear trap mind you) and not a drop of blood for 30-40 seconds sometimes.
I suppose they could have heated the long springs red hot on the ends and took the temper out of them, but it looked like it snapped pretty good to me if it's the video I seen.
was it a radio show stunt? stupid deal, looked painful.