True. The other factor that caught my attention is the height. An average 10-year-old might be like.. what? 100-130 cms tall? Imagine how smaller his stomach is than ours then. (by "ours" I mean ppl with 170-190 cms heights)
Oh and sorry for misunderstanding, Dan, I thought the kid's stomache did burst. D:
Anyway, a 10-year-old CAN die from that, simply because of the mere fact that his organs are too small to handle all that gas.
Plus you got the child's typical "curiosity", which might let him think it's somehow cool what happens to the gas in a soda when mixed with a mentos piece, and lead to something like this.