But seriously ...
I don't refute the story / storyline as it appeared to Sid (and apparently to the women) at all. I'm just trying to figure out whether there's a plausible mundane explanation that fits the circumstances as reported. I'm not trying to debunk anything - as I've often explained, I'm simply "scrubbing" the basic story / report.
The key elements I noticed were that the "wave" displayed a prismatic rainbow-style set of colors, the presentation of this prismatic color was stable (didn't waver or show shifts among the color), and it exhibited smooth continuous movement from Sid's hand toward / unto the pot the woman was holding.
Based on these elements I zeroed in on a favored hypothesis early on, and I've been querying Sid in relation to refining this hypothesis ever since.
I may as well toss this hypothesis into the ring ...
If there's a mundane explanation, it most probably involves a transient projection of prismatically-colored light into the scene. This projected rainbow light was discrete and stable in content, and it moved quickly but smoothly for a short time before disappearing.
Given the relative locations and orientations Sid illustrated in his latest sketch, the most likely natural light source was in front of him toward his left - in the direction of the door and what I assume was the shop's windowed front.
In the naturally-lit version, the light source was a glint or reflection from or off a moving object - e.g., a vehicle passing by outside the shop. This glint (whatever) was refracted to give the stable rainbow colors - maybe by a window / door glass, maybe via something within the shop. The movement of the original light source and the path along which it refracted / reflected (i.e., optically ricocheted) into / within the shop made it a discrete projected image that moved a short distance in a short time.
This passing projection of a rainbow chunk happened to become visible from Sid's vantage point such that it appeared first at his hand's position in his field of view, and its movement gave the appearance of the colorful "wave" emanating and progressively extending from his hand.
Its termination / disappearance coincided with reaching the pot because either the prismatic projection coincidentally ended or it became occluded by the pot itself.
A secondary possibility for the original light source would be a bright transient flare / optical "burp" in the fluorescent lighting overhead.
A tertiary possibility might have been a sort of chromatic aberration effect from light shining through the hole in the pot's bottom, probably involving reflections off the pot's interior.
My primary guess is that this moving transient rainbow projection was actually moving through its brief path / period of visibility behind / below Sid's hand. This is why I was asking about a nearby wall or a counter over which he may have been reaching.
If the rainbow thingie was indeed appearing in mid-air, my guess would be it was visible as a result of suspended dust. Another conceivable possibility would involve Sid having been wearing eyeglasses (a point I never got around to asking about).