Possibly suffocation but I don't know how we can be sure.
And it strikes me as not surprising that it was this individual that died a panic-driven, self-inflicted death. This snake was a natural born lunatic. A real screwball compared to the others. And while I'm sorry he's gone and that he died badly, the whole cage is much calmer now. Today when I changed their water they just watched me and never budged from their perches. Previously whenever I changed the water or light bulb this guy would thrash around, leap on his cagemates and instigate mass confusion with snakes flying in every direction. It appears that even at this level of the food chain there is some selection for sanity and a moderate disposition. :) - henry