This should end any talk on Death/Regeneration
Let's look at the evidence
Hartnell - Knew he was dying so he hobbled back to the TARDIS, regeneration happens before the show even call it a Regeneration
Troughton - Regeneration brought about by the Time Lords, arguable up until this past Christmas episode to not be an "official" regeneration.
Pertwee - Radiation exposure while battling psychic spiders. Makes it back in time to let Sarah Jane know.
Tom Baker - Fall, still manages to have words with his companions, so it's clear he's alive when the process starts
Davison - Exposure to deadly chemicals, he gave the antidote to Peri, then before regenerating said something about it feeling different this time
Colin Baker - Regeneration brought about from an attack by The Rani
McCoy - Shot. Yes he flatlined on the operating table, but after regenerating into McGann it's mentioned the sedative drugs delayed the process.
McGann - Died in a spaceship crash. As in DEAD. The Sisterhood Of Karn used magic to revive him and trigger the regeneration. They did a similar thing to Tom Baker, but it was before he died, thus preventing a regeneration.
Hurt - Regeneration just started happening, presumably from old age
Eccleston - Absorbed time vortex energy. Regeneration happened while he was standing
Tennant - Fended off a regeneration to grow his human counterpart, then absorbed radiation. Made mention that "it's starting" before his full regeneration hits. Regeneration happens while standing
Smith - Regeneration energy given to him by the Time Lords. Is clearly alive when he switches to Capaldi.
So there you go. In every instance sans McGann, he's not "dead" when the regeneration happens. Even McCoy->McGann has an out (well also that it was done by an American company that fudged on lore to begin with...). Notice The Doctor has never been beheaded or vaporized. He "stays whole" and is at least semi-conscious when the process starts (again, sans McCoy who was probably comatose).