TARDIS: Time and Relative Dimensions in Space
The Light: The temporal-spacial singularity bit that powers the TARDIS. In this series, The Light has been endowed with The Force (apologies to Star Wars) -like mystical qualities. The proper context for The Light traces back to the first Time Lords, including the guy who first engineered the effect, now known as Omega.
Regenerations: When a Time Lord wants to, or needs to, he/she/it can regenerated his/her/its body. The result, depending on the circumstances of the regeration, is effectively a new persona, with core memories and basic personality traits being retained: it’s a matter of a new body, not a new Time Lord.
As for this regeneration, it is controversial Eccleston quit the series after one season, giving the BBC people and early opportunity to show the new effects. But in all of the series, there have been multiple regerations, the first being forced by the death of the first actor. Then, whyenever an actor leaves the role, a new actor is cast, and a regeneration is written into an episode, usually under apocalyptic/baaaaad conditions. In the old series, during the Tom Baker/Scarf Doctor, a Time Lord comanion, Romana, also a Time Lord herself, seemed to purposely regenerate, just for the Hell of it. She even “tried on” different bodies, presenting each one for opinions.
I feel rather sorry for the ex-boyfriend/Doormat, and Rose’s behaviour towards him seems either maliciously or obliviously cruel. Then again, she’s 19, and beautiful, and presented as being a fairly careless person who has been growing up since her time travels. And the doormat is written as a fairly timid, useless, plodding git.