It's a mix of everything. Bitcoin's price crashes, some people are going to panic and some people are going to be excited with the low prices. There's no way to know which kind of person is larger in number. As for miners though, bitcoin was designed in a way that it will work regardless of what price it's at(besides zero, though zero is pretty much impossible).
Yes, that's why it's kinda hard to predict. As weaker hands start fleeing, further causing the price to drop, there would be vultures going in for a killing and buying those coins for cheap.