Fact #1 - You are a n00b
Fact #2 - You're friend is one of three things, a good hacker in which case he is probably on these boards with a name, a liar, or made up.
Fact #3 - There are applications being beta tested right now that can do some things that we wouldn't think is possible.
Fact #4 - The main things we believe to impossible (level warping) you never mentioned when you played the game. which makes this even more possible.
Fact #5 - This is no swapping of hex codes here... This has to be model injection.
Fact #6 - I worked for awhile on multiplayer AI and I doubt it's possible even with this upcoming program. Though I do believe injecting the models and animations is possible.
So what does this mean? If this is real and he releases it.. guess what.. it's a leak of some program unless he sends just the map file. We all know what happenes when programs get leaked.
You're "friend" is no n00b, he wouldn't have access to any of it if he was. If he's not part of this scene he must be part of the halo pc group.