This is a way to salvage a botched backstep. When you backstep it’s common for someone to hug your hips and force you over. Obviously the Sitting Switch is the best option but with pressure on your hips it can make that very difficult.
This is not exclusive to the entry shown on this video. Any time you are forced over with the persons arm across your belly you can use the Kimura to get back into the game. The important thing is that you understand the relationship of the elbow in the back of the armpit and the hip angle to really emphasize that pressure.
If locking up the Kimura forces them to disengage because they are afraid of the Switch or the Kimura itself then you can simply get back into the game via Open Guard or another reguard.
Keep in mind this is a triage move for when someone is trying to take your back. When you think of it this way very few things can go wrong positionally as you’re already headed for a terrible position.
