Peter Cushing is the Doctor Who David Niven
Part of me wonders if we've not had the whole story here. The 30 minute timeskip backwards wasn't used as much as I was expecting, although we can assume it gave them longer to put the plan in place and explore the 'you can't save her' bit of the story. Which makes me wonder if either we've got another 11's coat situation - so we might revisit this time once again - or it might tie in with Clara's exit, maybe we'll have a period of time when the Doctor knows she's doomed in some way but can't do anything to change it - and she's oblivious.
Was it established quite why the Tardis didn't want to hang around at the station? I thought at first it's because there were two Doctors there - one arriving, one in the suspended animation coffin, which makes sense - except instead it takes him back where he came from thirty minutes earlier, which was *also* a point in time where the Doctor is there twice. So... I dunno.
It could be an oversight, but I'm not sure, my gut's saying there's more to this.