I think most of the Doctors have viewed their impending regenerations as, at least, something akin to death. The First Doctor regarded the Second and Third as inferior “replacements” when he later met them. The Fourth Doctor spoke of his demise as “the end.”

It’s each new Doctor, at the beginning of life, who is more likely to regard regeneration as a way of staying alive. For the new Doctor, continuity of memory and experience is preserved, so the regeneration is not a death but a change. The Tenth Doctor comments on his “new teeth” because he remembers, just minutes ago, having different ones. Likewise, even though he dreads his next regeneration, Ten is perfectly content to claim the destruction of the Daleks and Time Lords as his doing, because he remembers doing it.

While covering the Fourth Doctor, also spend a bit of time on Romana’s regeneration, which is very different from any of the Doctor’s. In complete contrast to the Tenth Doctor’s fear of death, Romana changes bodies the way people change clothes, even trying on a few first. This despite the fact that the personality change between Romana I and Romana II is actually quite severe.

Likewise, when covering the Third Doctor’s regeneration into the Fourth Doctor, see if you can find anything on the regeneration of K’anpo Rimpoche into Cho Je. It’s the first time we see the “projection of a future self” idea that recurs (in a much less developed form) right before the Fourth Doctor’s death.

The scenes with Rassilon and the Council in “The End of Time” take place on the final day of the Time War, as they learn that the Doctor is coming to wipe them out. The time lock (whatever it is) seems to be already in place, since they can’t just pile into a TARDIS and escape their fate. Instead, much as the Master arranged for his own resurrection by the Cult of Saxon, they set up the Master as a tool to pull them (and Gallifrey) directly from that time before their destruction to the Doctor’s and the Master’s present. Of course, before Gallifrey can materialize, the Doctor and the Master send them back to the last day of the Time War, shortly after which the Eighth (or Ninth) Doctor shows up and kills them all.