He's sporting possibly a two-tone baseball cap (although it would appear - on first inspection - uniform in colouration -- especially in the final frames).
It has a prominent-enough beak - curved in (downwards) by a moderate degree - along the left and right hand periphery.
We see him staring straight-ahead as he appears in the field of view.
We see him appear to either hesitate (and/or) stutter-step in the first frames of the released-video.
It's possible he may have kicked himself (in the opposite foot), as his shoes appear very close together in the half dozen frames. Perhaps he dropped something in his coat (inside his coat) and bent at midriff (out of f.o.v.) to prevent perceived falling-object from falling out .. the bottom. He's seen adjusting something (under coat) in later frames.
Or perhaps he has to relieve himself. His legs are particularly close together - like he's got to "really go".
He regains stride (however stilted) and momentarily looks left toward the large windows next to the service doorway - missing all together: the camera above the door.
HAL is suggesting the guy as no criminal-Einstein and further: that (he) most likely had not "scoped things out" previously (seeing how centrally the camera figures above the well-lit entrance-way).
He's sporting some sort of unusual; large, loosely-worn bandana. The shadow it forms (casts) is unusually deep -- lending currency to the "turned-up-collar" conjecture.
One would think that given there was an eye-witness .. we would have a better description of the perp's apparel. Was it a two-tone cap? Was there anything noteworthy about the cap? A logo? A lack of logo?
Was the perp wearing gloves?
HAL recognizes, even with his ice-cold, forever-calculating, brain-less silicon-circuits -- the appalling horror which must invariably have presented itself. And, (that) it is commendable the witness (witnesses) were/was able to advance any reasonable description - in the first instance.
