the problem with that video file, as Cycrow already said, is that it is a whole long video file containing all the video snippets you see in game.
Those clips are timed and the game accesses to them via time codes, so there is no way of editing it without messing up all the other video files. Unless you append to it some new clips (or pictures stills) and then are sure to recode it back to the original format. Believe me, it is a titanic work and no grant of success.
Then you should replace all the time coded calls to point to the new scenes, thing i'm not even sure that might be done... (don't know if there is a Tfile listing those or if they are hard coded - and personally i don't need to know since that 'mod' is something i think no one wish to waste time with
