Dangerous Submissions that Cause Injuries!

What is the most Dangerous move in BJJ? What submission that seems harmless has actually caused the most injuries? There certain moves and techniques in Jiu-Jitsu that don't appear to deadly- next minute you have yourself a knee reconstruction. JT & Joey have experienced first hand some injury makers but they seemed to come from nowhere... This episode is a word of warning to make sure to be on high alert because some moves are more likely to injure than others, your BJJ training partner may not even see it as a real threat before it's too late. Is there a sneaky move you know that is more dangerous than it seems...?