Maybe I misunderstood up-thread, but don't think this gymnast has ever performed this skill correctly. This isn't something the gymnast feels prepared to do after 1 week of practice on the low beam.
That being said, I think this sets up a perfect scenario for a gymnast to not trust their coach. This approach would make more sense if she'd been doing it on the low beam for weeks and months and just won't do it on high beam, but after a weeks practice I think it is clear that this is a skill she does not feel comfortable performing. Regardless of whether or not she got up there and did it, I think the bigger issue is the damage done to the coach-athlete relationship. Kids shouldn't be pressured by fear and threats to do skills. Sure, they may do them some of the time, but long-term that style of coaching will damage the relationship and potentially the athlete.
Coaches should not be bullies and this feels like bullying to me. I am not a coach, but as a former athlete I can say quite clearly that that approach would not suit me. My DD would not likely respond to this either. She is 9yrs old and is competing level 7 and I can honestly say she's never been threatened "do this or else". Lots of repitition, progressive skill building, going back to basics if needed, proper conditioning, etc are the tactics employed by our coaches and they seem to work quite well. The athletes are pushed appropriately, but none of them are afraid of being kicked out if they mess up or can't do something.