Jeff glover does a variation on this same takedown.. But he pulls reverse guard, then swivels into it.. It's wild stuff, I'll see if I can find the vid.
I'm getting jacked up with leg locks... it's almost embarrassing... who's got the links to some good leg lock "D"... Looking at you Brent Smith, Mike Dewitt, and Coach Herzog.
Prevention my friend. Prevention. A leg lock master gets your legs, and it could be no getting out. Same answer I'd give for any sub, really. I'm sure there's awesome defense and counters out there though.