UNDERSTANDING DEF VS HEADLOCK FROM BEHIND
Krav Maga's self-defense curriculum assumes it is a system that works from a disadvantage. This is in my opinion a necessary evil (like fighting from your back and looking for opportunities like getting up) but can also be bad for the system (like defense v gun hostage from behind, sitting, hooks in and headlocked-wth you REALLY messed up to get in that position for that one).
I can only speak for my experiences in the Krav Maga world of this endless debate that I've been asked numerous times in regards to this topic: Do you turn left, or do you turn right?
My answer has always been, "yes"
The more factors involved in the question, the more room for dire consequences. However, the better you protect the circumstances that are in YOUR hands, the less chances for the full sink. Here are some factors for consideration: TIMING, SPACE, POSTURE, and ALIGNMENT,
TIMING: curb the sink of the interlocking by SHRUGGING the shoulders. Pretty hard to strangle a person with no neck.
SPACE: prevent the primary attacking hand from interlocking by occupying space. The principle here is real estate. Every fraction of an inch he sinks, you are losing. Hook onto that arm fast and SPIDER CRAWL your fingers far as you can into the palm. If you stop the locking mechanism, you stop the sink.
POSTURE and ALIGNMENT: If this is a grappling scenario and you are BOTH on the floor and he has your back, one of the guiding principles is that if his chest is on your back he's aligned for the choke. The term we use is "find the floor" but I'm sure it has other names. If you're a student of the school, pause the video at SHOULDER PUNCH and make the contrast that find the floor and shoulder punch bear the same posture. If your line of learning (name drop) bears resemblance in a multidimensional fashion you will integrate skills a lot better in a multitude of ways.
Going back to my answer in the question of turn left or right: my answer is learn how to use a push pull concept because understand your attacker is a human being with his own decision making process.
If you know turning left well, you'll better understand turning right.
Do what is hard today, do the impossible tomorrow.