The stunt went wrong when he failed to pick the lock and was seen kicking his legs before passing out and being dropped, unconscious, into cardboard boxes at which point the show went to intermission. Producers later explained that the stunt had pre-arranged safety measures, meaning Goodwin's life was never in danger.
The stunt went wrong because he couldn't pick the lock and ended up being dropped unconscious into cardboard boxes. Producers explained that safety measures were in place to ensure Goodwin's life wasn't at risk.