Can bitcoin go down, of course but to think it can go down that much that fast is to ignore the fact that a lot of things have happened since then, no exchange is as big to cause that fall so if you want something else to cause that fall the only thing that comes to me is mining, it is the only thing that is as centralized as it was Mt Gox back in the day, but how can the miners crash the price in that way? I do not know.