I think that voice-over may have been recorded specifically for the trailer. It shows blue-prints and other things that, in the game, Raz explains instead of Dr Loboto. It wouldn't make sense to have Dr Loboto re-explain what the player already understands thanks to Raz.
If it did get cut, maybe they decided the player should know what the brains are being harvested for at the beginning, instead of finding out at the very end when it doesn't matter anymore. Hence, Raz talking to himself instead of Loboto talking to Lilli.
Just a thought.