That sounds like a good, thought-provoking (or emotion-provoking!) assignment, squiggle! I think you've got a good start on it.....
I understand the shut down vs melt down too - it's just such a habit for me to shut down the huge emotion, so I can handle it, control it. The thing for me is that I am so controlled I don't know how exactly to melt down, at least where people can see it! Now, I have had a few huge temper tantrums, really blowing angry fire out.....but not with anyone to see or to judge, because I am afraid of anyone seeing how fiery my temper really is. So I have worked hard for years to appear very, calm, cool, controlled.....and I do. Even in therapy, I do. Even when I am talking about my pain, I do. Even when I am feeling tremendous, terrible, heart-squeezing, breath-stealing pain, I do. And I want to let go....like you, I want to lose control. But before I can do that, I have to let go of the tight grip I have on it.....if you get some insight on how to do that, I'd love to hear it!