Where did you get these low speeds from and landing flaps were they??It would be Flap 15 if already established in the Go Around and gear pissibly retracted and olane accelerating..very fast cobsidering the light weight they were at.And talk of physics laws..they apply to meteorology too and heard of chaos theory?Let the recorders explain those laws.You and I are just guessing our way through this riddle.
Most airlines insist on "stable approach" criteria being met at various points on the approach, the gear and flap would be selected accordingly.
Flap 15 by the way is listed as a landing flap option in the FMC, either way, stable approach criteria being the target, the aircraft would be in a low energy situation, I think I've only ever seen military fast jets transitioning from low energy to vertical flight, I would think a loop flown by a passenger jet off an approach rather unlikely.
The pitch down is the more probable scenario due both to somatographic illusion and the requirement to trim forward as the aircraft accelerates away from the low energy approach config.
Yes, you could say guesswork, but I base it on many thousands of hours flying the NG. As regards "chaos theory" I don't remember anything about it in ATPL meteorology.