When someone is trying to break your arm, there is a natural tendency to panic. One way to overcome that tendency is to practice escaping from armbars. Look at Bradley here (I have no idea why he is so happy about this drill), he is on top with both hands on his partner. This is where we would start the drill where you are almost in the armbar.
When I say "hajime!" you have 10 seconds to either get the armbar or (if you are on the bottom) to escape. This drill is good practice for the person on the bottom in escaping from the armbar and the person on top in finishing it. LISTEN! If you are the person on the bottom, your main goal in life at this point is getting your elbow on the mat. If your elbow is on the mat, the most they can do is pull your arm out so it is flat against the mat. That doesn't really hurt.
Here's a picture of the exact same position in a tournament:
Another advantage to this drill is that it allows you, as a coach, to watch how your players are doing armbars and make sure their technique is perfect. For example, Crystal! (yeah, I'm talking to you)
And Bradley, yeah, you, all smiley in that photo above. You see how Crystal has her body up against that arm. That's how you should be.
The armbar escape drill is supposed to benefit the person on the bottom who practices getting out of an armbar so quickly it is a reflex, but, as you can see, it can benefit the person who is applying the armbar as well, especially if you have an alert coach available to correct any mistakes.