I have struggled with this myself, and have come up with this as a closer:

"I know you might not understand how everything that happened tonight happened, and that's kind of the point, but realize this: When you know how it works, magic is boring, and most of it could be done by any one of you if you applied yourself. If you want to see a REAL miracle, if you really want to be amazed, be in church this Sunday morning and spend some time with God. He's the only one that amazes without having to pull the wool over your eyes."

Closing with that has alleviated my concerns.

Commenting for future reference. Thanks

I admire the fact that you're not misleading people into thinking you're doing something supernatural. Maybe try explaining it in terms of psychology. I think people will still be impressed.