My fundamental answer isn't going to change, but I will approach it from another angle.
You've identified a problem that many practitioners have to deal with. If they've never been involved in the world of sports, then they may not be used to the amount of focus that is necessary in fighting. It's a mindset centered on "what do I have to do right now?".
Anger is the enemy of focus. It can either make you reckless, or as in your girlfriend's case it can make you shut down. Whichever way a student or fellow practitioner tends when they get angry, the way to approach it is the same.
- You have to face the internal demon--so you have to get to that ragged edge and choose not to give in.
- You deal with it by teaching your body to move without the need to think about the move
- You also have to build confidence in your training
That is why I suggest technique sparring. If you are used to point sparring, or one-steps, all action stops when the point is scored or the technique is complete. You don't have opportunity to stretch your focus.
- Go over the techniques and combinations she should attempt to use
- Keep sparring for a certain amount of time
- If the other person starts to shut down, find a cue that gets them back in the game. The shorter the cue the more effective.
The technique sparring forces you to keep going and get closer to your ragged edge and face your demons. When you get to that ragged edge, you have to simply choose to focus on what's the most important thing right now. What I've seen in people who tend to shut down is that they are feeling overwhelmed, and that manifests in frustration, which works against them. When the combinations and techniques they are learning start to click, it's less to worry about. However, the discipline of shutting out all the unnecessary thoughts and only focusing on the fight at hand is not easy.
I think it is more constructive to use focus rather than anger. Focus is an aspect of many different sports, and is a very constructive force. In short, the challenge is to empty the mind of all distractions. From thoughts of winning and losing, from thoughts of anger and fear. Simply focus on the fight at hand.
You can only maintain that kind of focus for so long, and it takes time to develop it. It's not too different from the concept of a basketball player standing on the foul line with the crowd doing their best to distract the player. The player, when they are "in the zone", doesn't even hear the crowd. They simply see the basket and focus on the one thing that is necessary.
I would not be surprised if what we are trying to express is very much the same thing. However, different words are sometimes necessary to express the meaning.
To help develop the focus, try an approach my sensei uses with me: technique sparring. Technique sparring doesn't stop with a point scored, or when the technique is over. The goals are:
- Perform the techniques in a sparring situation
- Continue moving and be prepared for the next attack
- Focus on the flow and movement of the technique
If the techniques are effective, they will work. It takes time to build confidence in the technique, and build up the automatic response of how the body needs to move. Muscle memory, if you will.