[sailfrog]

Insofar as Nanex is concerned remember they are attempting to sell you a product, so be aware of their motivations before swallowing any unsubstantiated assumptions. With that said from what I have seen their charts are accurate but the interpretation of what they mean is sometimes a bit dramatic :)

I can't speak directly to the BATS IPO debacle but I can say that when the NBBO in a symbol is locked or crossed (market speak for the bid and ask being the same or being inverted) matching engines can ignore the NBBO. This results in trades being executing at prices all over the map and can explain how a stock can go from $15 to $1 almost immediately.