Actually, its a bit of an fallacy that Bc's dont relax indoors.
True, they are hyper working breeds, and the joke about BC's and the lightbulb is pretty much on the money.
However, its not just quantity, but quality.
As in, if you give them the right 'sort' and amount of mental and physcial stimulation, you can get them to a point of being reasonably quiet indoors.
I've fostered quite a few myself, and they do settle and relax in between the high arousal states.
The reputation is so strong as many people that get them just dont have the right lifestyle or the right head for these dogs, hence the stories you hear often.
Sounds like this lady has both.
The trouble is they are quick learners, and when you train them, they pick it all up super fast, its what you do with them afterward that counts!
Otherwide, they get bored.
I know someone that has 5, and she aint no spring chicken, and isnt exactly built that good herself, if you know what i mean.
But she does agility etc with them, and they are calm enough.
now, if you said dalmations.........BC energy level without the ability to learn as quickly and the consequent ease of training and control.