Did the same at a school trip, after taking off the film I thought I could tear the camera apart, thus exposing the cap connection. Left hand fingers would lean peeerfectly on these metallic parts when playing with the flash.

It became a game between kids. The shock was more intense than harmful, although I saw two white dots on my nail that I assumed was due to the shock.

Today I rip microwave ovens, but I carry gloves and remove caps before anything else.