You know very well that Strictly is as much of a personality contest than a dance contest, and always has been.
Also, if the contestant is well known, popular and a great dancer many people won't vote for him because they assume he is safe from the dance off.
A lot of viewers also champion the non-dancers who have to struggle to get through the routine and don't like those with dance experience - they think they are 'ringers'.
I assume Tameka was in the dance off because a lot of people assumed she was 'safe' and didn't vote. It could well be Naga off next week because viewers haven't taken to her.