The basic advice on taking the effort to place limit-orders or stop-buy/stop-loss orders instead of market orders seems good whatever the case.
I have an example from 27th Oct, before expiry. Market was breaking down rapidly and had broken 4900. At that time, Level II showed no sellers 4900PE and 5000PE.
Now this could have been a broker's data problem. But 5000PE showed no sellers on two occasions and less than 5K selling volume for about 2 mins so it is unlikely that this is erroneous data.
Wish I had a 5000PE to sell (did have the time to take a screenshot). It would have been a nice experiment to place a limit sell @200 to check if it filled somebody's market order.
(Apologies, the screengrab is wide).