Two things... me and my friends (Keioske and The Lost Fox) killed a BOB on lone wolf a few days ago. I remember (being dead at that moment) going Kill that guy quick! He did do the deed but nothing happened....
On another note...
I can get out of the level even easier than you guys...
1. Start the film.
2. Fast foward till you start moving around.
3. Pause the film.
4. use the back button to get to the start.
5. Press B then Y
Bam! outa the level! Works in any storymode (I tested it)
Downsides: You cant advance the film and once you get inside the playable area you have to repeat the process to get back outside.
On lone wolf, if you do this trick, all the dead marines are standing there where they would normaly be but the spartans arent... In games if you want a dead body, it is common to place a person (marines in this case) and modify thier HP to 0, so that when the level starts they die. Its easier than having to actually put the body in the exact position you want it in. I dont really know why they didnt do it with the spartans though. I suggest that you do the zombie trick on a marine as well...
That reminds me! On lone wolf some of the spartans are wearing armor that we dont have access to! Gungnir helmet, security helmet, Jun's shoulder (the one with the ammo in it), Jorge's Shoulder, Emile's Shoulder (No knife), Carter's right shoulder (I can see the left one in my armory), and Carter's chest. Those are the ones I can recall...