^ I agree with Starkers other than Jenny, 3 (out of 4) regenerations so far have been in the TARDIS.
Actually, what I really find odd about the regeneration scenes is that every Time Lord in the New Series seems to insist on regenerating standing up. In this episode we see the Tenth Doctor insistent on hauling himself up off the floor to a standing position for this purpose. Not only that, but the regeneration position of choice seems to be with a legs-wide-apart and arms-out stance (even before the actual regeneration happens)...when the Master regenerates in Utopia, we see him almost deliberately arrange his body in this fashion.
This seems to differ from the old series, where most of the time, the Doctor regenerates lying down.