She used the phrase incorrectly while speaking extemporaneously.
The phrase is normally used to highlight a core point within a lengthier dialogue. That isn't what Selena was doing - she was correcting herself and introducing a correction. It makes no sense in that context.
It's quite common for idiomatic phrases to become overused in the speech of an individual to the point that they use them out of context. For example, an ex-manager of mine would use the phrase "from a [x] perspective..." to introduce every new thought he had. It was extremely irritating! Funnily enough, a commonly overused phrase is "I mean to say...", which some people overuse to the point of beginning every sentence with it, but actually, that would have been the perfect phrase for Selena to correct herself with.