I believe the map in the game is called "The Slient Cartographer". I don't recall the sergeant being there at that time though.
This sounds the most right out of any of them. I remember a video with the Seargeant telling you to buy Halo. That is most likely an earlier version of the SP Map "The Silent Cartographer." (Like if you look on the back of your Halo box you will see banshees in The Silent Cartographer, but in the released game, they are non-existant). <- Oh, and I think it is only on the non game of the year edition. :icon_bigg
I dunno about that, but this picture is definatly from the end of the downloadble trial when you quit. You can't force out of it either, so when I got done I would just CTRL+ALT+DEL so I wouldn't put up with his "DO YOU LIKE WHAT YOU SEE HERE?! WELL..."
Definetly from Silent Cartographer level and definetly from the end of the PC version demo, but the guy looks different then I remember. I think OXM had it before and I think Oddworld or one of the launch games might have had it too.
Have fun. This one is from the Xbox version, but it's extremely similar in the PC version. http://youtube.com/watch?v=krXLIXes8q4