Re: Name that technique:
I'd say it's sankyō (kote hineri) with the suspect being a non-compliant (and non-pliable) aite, rather than a trained uke that knows how to preserve herself.
Anyway, if you carefully watch the footage, you can see the police officer slip in, at the same time "corkscrewing" her hand, followed by taking her tegatana with his right hand. (That initial part looks a bit like what my sensei does when he is trying to jump to highlighting the details of the takedown, rather than to demonstrate the full attack response). The officer's left hand is completely free during the takedown. The corkscrew, the tegatana grip, and the free hand would seem to indicate sankyō (kote hineri) rather than ikkyō (oshi taoshi).
During the takedown, he kind of jerks his body rather than properly using his hips, which would indicate to me that he probably learned the technique in a self-defense crash-course for police officers and security guards (so he probably didn't have much time in class to learn about "preserving uke"). Even with the officer's body movement being jerky & ugly, I'd still say he was doing the small circle variant of the sankyō takedown, which seems to be the less common in Aikido (by my limited experience). At the same time, I have had some partners that seem to prefer the small circle version, so it can't be too uncommon. The small circle version feels like it leaves a smaller margin of error for uke (my experience as uke).
At any rate, the course instructor could well have been an Aikido or a Hapkido practitioner. Hapkido also uses what we would call sankyō, and they largely use small circle variants, so perhaps it's that, but I've willing to chalk up most of the variation just being due to the suspected crash-course learning I mentioned early.