Trying to finish up some of the Riddler Physical Challenges and having a bit a trouble with this one. I thought I just had to grapnel a ledge below an enemy and use boost but that doesnt seem to be working. Can anyone explain exactly how this works?
You need to aim just a bit below the edge. Hold down the A button and you should automatically do the take down. Another thing that may help is getting their attention in some way. If you do that they'll stop patrolling and stand in one place...usually.