I found No Russian to be the funniest mission in a video game I've ever played, not because of the killing of virtual innocents but because of... actually I don't know why but the whole thing was extremely cartoony and tryed to be srs which I guess is what I found funny about it.
Mikel's theory is almost exactly like the one I thought of. It felt like the kid was somehow antagonistic and I too wondered why there were so many traps laying around that seemed to only be there to stop someone. To me it seemed like the kid was sinister in a way that made everything in the world afraid of him and need to defend themselves against him but fearful when they realized there was nothing they could do to stop him. It is a common story-telling trick where the actions are perceived by the main character one way but instead are often completely different when looked at from everyone else's.