I had an enclosed MRI a couple of years ago, and could have went to sleep inside the tube if not for that clanging and banging!
I've never been claustrophobic, and used to frequently go spelunking with my friends... who've all 'grown up' now, and no longer have time for such things. :roll:
Sorry to hear that it bothered you, and I know just how you feel because I have had acrophobia all my life... though it's significantly lessened as I've grown older.
My dad used to tease me when I worked construction with him after I graduated high school... his nickname for me was 'ground squirrel'.
Coming through the enclosed MRI with no problem gave me the ammunition to pay him back for his teasing, because he couldn't stay inside long enough without being sedated... and even then he barely made it!
For me, it's a matter of reasoning with phobias... I'm afraid of heights because I know there's a very real possibility of falling, but enclosed spaces don't bother me as long as I know I'm not actually trapped.
It might be a different story if I really were trapped in an enclosed space, but fortunately I've never been in that situation to find out!
I don't know if that story or my reasoning will be helpful, because I know that phobias are often very unreasonable... but I wish you luck, and I hope you can get through it next time.