So I tried something- I very lightly touched two fingers to the front of my larynx (Adam's apple) to remind my larynx that it didn't have to lift to hit those high notes.
Darned if it didn't work! Just this slight suggestion to my automatic nervous system was all the reminder my voice needed, and I dropped the tension trying to build in my voice. I first heard of it from Boston vocal coach Jeannie Deva, who uses it in exercises to remind the larynx not to lift. It's a bit of an advanced technique for the recording studio, but it can come in very handy if you learn to use it in such situations.
Let me know if you try it, or want to learn it.
Lastly... sorry for the blog post about that MTM video again.. I was doing some experimenting with sending YouTube videos to my blog. I thought it was just a draft... I didn't know it would publish automatically. Duh. I deleted from my blog, but you'll have to delete from your email box. Please pardon.