You talk about alternative translations just before the segue into Morris' quote that "vibrated" would probably be the most appropriate translation, but presumably dismiss the gap theory on the basis of the English "text" as the original language does allow for it.
Looks like unvarnished "special pleading" to me.....
Not a good way to demonstrate 1Thess 5:21 if you ask me.
There are reasons why I dimiss the gap theory, but I didn’t write this as a polemic against it. Morrises quote about the movement of the Spirit across the waters, possibly meaning “Vibrating” doesn’t seem to do any damage to the text seeing that the same word is rendered shaKe and flutter.