Did MDY really go down to 23?

[scp]

On Nov 6? How did that happen?

[Car Insurance Guy]

MDY - Bad Tick

SCP - Yes, MDY could have traded at $23 for one trade. Some investor threw a sell order on and an astute trader picked up MDY at a deep discount. I say probably, because I'm only looking at it in Yahoo Finance. You hear there's sharks in them-there waters. You may have found one on the MDY chart.

My boss has been trading funds for decades. He says never use a market order for ETFs. Even for one as liquid as MDY.