As an episode I thought it was okay, but not fantastic. There were some nice bits, but to some extent the plot didn’t overly seem to hang together. After having built up the whole concept of the sisters essentially breeding humans to act as cures – a parallel to arguments over creating embryo’s for genetic research – I though the whole resolution was really just too easy, with the Doctor apparently managing to cure all the bred humans rather easily.
Having said that, there were good elements. As before there was a good dose of humour, using the old body swap plot device to give Billie Piper especially a chance to play a different personality. Also David Tennant seems to be getting in to the role, with a good chance to show a variety of emotion in this episode.
Interestingly, this was the first time watching the new series that I thought ‘I’ve seen that before’ in terms of locations. It happened in two senses, firstly, when they went into the back corridors of the hospital, it looked rather like the location used for the final scenes of Rose back in series one. However, in one of the chase scenes, it did strike me that they recognisably went down the same gantry and staircase, a bit reminiscent of the ‘these corridors all look the same’ joke in the Comic Relief Special a few years back.
On the basis of the series last year, I tended to not be overly impressed with the episodes written by Russell T Davies, and this episode seems to continue that pattern. Certainly I’m looking forward to some better episodes later in the series.