"...someone sold at say $5 or $10/share..."

$5 or $10? Try $28.00...

Right now, anybody doing a buy or sell at market, of more than 500 shares would be in for quite a surprise...

The level II page shows:

Bid

• 5000 x 0.245
• 500 x 1.01

Ask

• 500 x 2.50
• 200 x 28.00

So a market buy or sell of 600 shares could make the price jump to 25 cents or 28 bucks!