this is really good: https://www.youtube.com/watch?v=wB2YNAaKnZU

for context: The sixth doctor never got a regeneration story, and didn't regenerate on screen, due to the BBC being jerks. So in 2015, they made an audio drama which told the regeneration story, The Brink of Death. The video that I've linked is an edit that takes the audio of the regeneration scene, and combines it with bits and pieces from the TV show, to make an approximation of what it would have looked like on screen.