I've got a recording of this episode. I've watched it over and over again, and every time I watch it, I see something new: how the Doctor calls for Martha, how he admits his fear, how Riley notices Martha almost right away. On the surface, it's a ticking clock episode, but underneath, there's a lot of character richness. I think it's one of the best episodes of the season. it holds up viewing after viewing.

And yes, Tennant does tall, thin and tortured with the best of them. Man, I love to see him do angst. ::grin::