Yes, like the rear naked choke, I think it's hard to get out of. Assuming it's not applied by a professional I think there are ways to get out of it. Some better than others. The two that I researched: 1) Duck down and towards the arm that is bent back while grabbing the arm that has you and strike at the elbow joint with the other arm. This assumes you can get a hold of the arm that has you. 2) Also, a duck down with vicious strikes to the head and/or body to the point that he releases your arm. Neither are foolproof if he already has your arm locked in.