She is very much not alone, medicine is a bit like that - everyone is excellent and being rejected is usually the first time these dc have failed at anything in any significant way, so it is hard to take. I know someone who had an average UKCAT (but everything else, including work experience, excellent) and 4 rejections. They were very despondent, but kept working hard to get excellent A levels, then got themselves good work experience for gap year and worked hard at UKCAT practice and achieved an excellent score (way, way higher) second time around. Unsurprisingly, the reapplications were much more successful, so it definitely can be done.
You need to encourage your dd not to give up, but to keep working hard. IB is notoriously tricky and she needs to actually achieve those predictions to give herself the best chance next time - if she needs a next time. As others have said, it's not all over yet, but she needs good results either way.
I don't know much about BMAT other than that it's supposed to be difficult and only a very few very choosy universities use it, so I don't know how easy it is to improve on. I do know a number of reapplicants who have been offered places at Birmingham, which everyone who goes there seems to love and they don't use BMAT or UKCAT (but do like very strong academics) - worth a look if she does end up reapplying.
If it cheers her up at all, I know a girl who has quit Cambridge medicine after 2 years as she hated it. It's very theoretical and from the small sample of medics I know seems to be a less enjoyable course than many of the others. It is said for medicine that it doesn't really matter where you study it - all the junior doctors start out in the same jobs on the same pay from all the med schools.