Originally Posted by JuanOrtizSr
The environmental one is story-related unless you just rushed the sniper or jumped through the window.
Thanks for the head's-up to those whom haven't gotten yet.
Yeah, my first time through I used a remote control batarang to knock him down and then ran up to finish him. Didn't even notice the room to the side until running back through the area later.
I think it would've been better if they FORCED you to go to that room. Not for the sake of the achievement but just to showcase the ability.