I had expected Takahashi to be one of the more energetic dancers in this PV as well, mostly because she is argueably the best dancer in the group and one of the best in H!P.
but, maybe her supposed 'lack of energy' was intentional. I think that even though some of the girls were tired for example, while doing the PV, they'd still have to give out as much energy as they can. the PV always has to be as 'perfect' as possible. I mean, if one of the MM girls are in a bad mood while doing H!M (another example), they still have to at least pretend they're not and be all smiles.