this has happened to me a few times soloing, as well as a party - 3 of whom got killed instantly, having more than 3/4 health full...
--i doubt this is intentional, tho i could vision chase sitting behind his cpu fiending with his finger on a button that casts lvl 99 fireball explosion...
--another thought would be that the scripts in the planes often eat stale bread for lunch, and thus become constipated....releasing a instantaious chain of explosions out of frustration at the fact that you are killing one of its spawns
it doesnt happen often, but if someone was soloing and gets pwned by this act of firey karma it would stink for them