Bitcoin price valuation depends on the projection of past to future prices.
Or do you think people will check the fundamentals, conclude a price of 5.7 and stick with it?
Over the course of 15 minutes? Yes, I think they probably should.
I'm not saying never change your mind; I'm saying if you think your bitcoins are worth $5.65 then the fact that someone sells 40,000 of them in a blatent price dropping attempt shouldn't be enough to make you suddenly value them at $5.45.
...
Oh look, we're
about have passed $5.75 again. Now that we're at that point... everyone ask yourself "did I profit from my actions over the last hour"? Did you instantly adjust your sell price to fill in the gap left by the big dump? If you did, then you gifted your profit to the person with the deeper pockets.