That's just the reverb tank springs bumping around. But the opamp circuitry it's connected to amplifies it so much, you get a horrendous crash. Even gently knocking those springs together will create an explosion of sound.
Physically there is little or no chance of damage to the reverb tank or springs. This page shows what's inside:
http://sound.westhost.com/articles/reverb.htm
So imagine what you would have to do to shake that tank to the point where the springs break. In practice, you probably couldn't even if you tried. If it did break, it would probably be a simple matter of unscrewing it and hooking the springs back on to what whatever they are supposed to be clipped to.