I don't have any hard evidence on how Black Friday happened, so I can't say whether it could happen again.
Black Friday was a sickening one-day loss for me. But it worked out in my favor, since I had completed my planned initial sale and then I sold more after the plunge when we got back to 16-17 cents.
I now have all my shares back -- and my initial investment in cash.
If Black Friday happens again, my guess would be that it would happen at a higher price than 28.