Sure you can "stack" them. If you place a sell order larger than any of the buy orders on the exchange, then what you will see is a "stack" of executed orders beginning with the highest-priced buy order and working down to cheaper ones.
In any case, the bounce back looks to happen over ~100 ms or so, which is plenty of time for anyone's strategy to catch up. I don't see how you can conclude there is some big player who knew "well before the event."
In any case, the bounce back looks to happen over ~100 ms or so, which is plenty of time for anyone's strategy to catch up. I don't see how you can conclude there is some big player who knew "well before the event."