How Did I Explode A Saucepan?
I work in a commercial kitchen and I've seen this happen before, which is why we do not use copper-plated cookware. This can happen whenever you have two different alloys welded together and apply heat to one side or non-uniformly; An effect known as 'thermal shock'. What happens is one metal expands faster than the other, causing a deformation or fracture. Think of it as one side trying to 'pull' the other at the edges. The pop you heard was undoubtedly this delineation occurring, followed by the kinetic reaction of the pot jumping.

I find your claim that the pot leaped through the air difficult to believe, but I have observed audible pops and visible movement when they fail. If you have a flat top (like an electric stove), it could skid for up to a foot from this due to the lack of friction and possible presence of condensate (water) on the surface which can at certain temperatures act like a nearly friction-less cushion. Oil doesn't do this, only water.

If you've ever been in a commercial kitchen you'll notice every cookware item is made of a single cast of metal (most usually stainless steel) because of this. Welded alloy pots and pans just don't last very long -- the effect observed so violently happens at a smaller scale with every heating cycle, eventually resulting in ruined cookware. Also, being a line cook means being exposed to things exploding, dying, catching fire, etc., on a near-daily basis, not to mention an assortment of knives that would make most Hollywood bad-asses blush, so obviously we try to limit the number of things that can go wrong.

Do yourself a favor -- if you stick with the copper-bottomed pots and pans, make sure to put plenty of water or oil in them. Heat with nowhere to go will cause failure quickly.