Thinking about it, wasn't Commander Strax dying in "A Good Man Goes to War" ?
"... It's strange. I have often dreamed of dying in combat. I'm not enjoying it as much as I hoped. ...".
... but he didn't actually die on camera, he just looked very ill.
That might make sense if the new episode was earlier in their timeline, but not the Doctor's. Of course, then he wouldn't have met Madame Vastra and Jenny, so that doesn't work.
Presumably Strax is going to have turned out to have made a miraculous recovery.