he isn't "killed", his neck's twisted thanks to his powers being counteracted upon by a virus made of his own dna.
obviously he'll just get back up and beat the crap out of them, but it's a nice effect to see how the only thing that they could find to take down the Hulk (however briefly) was - essentially - The Hulk.
but the guy says hulk coudl move at 300mph! : Q: Exactly how strong is the Hulk?
A: Well, he's pretty strong. In the film, the Hulk can cover 3 to 4 miles in a single leap, can achieve speeds of up to 300 mph, has an impenetrable hide (8 to 10 times the strength of regular Kevlar and incredibly regenerative), is capable of lifting 100 tons, and finally, based on punching power and weight, the Hulk would be able to apply at least 14 tons of pressure per square inch to whatever he smashes.
i thought you guys might want to read this : (an extract from an interview with the writer of the book ' the physics of superheroes' where real physics is applied to comics
lol here's an extract :
NRAMA: There’s always that old joke about who would win in a fight between Superman and the Hulk. But can that be explained with science?
JK: From a physics point of view, I would go with the Hulk for the following reasons: the angrier he gets, the stronger he’s going to get. There’s even an explanation for this because as he’s getting frustrated there’s more adrenaline pumping in his system, so that’s a trigger for increase in his strength and if he keeps pounding on Superman until it was nighttime then Superman won’t be soaking up any solar radiation and he starts getting a little weaker. So I think eventually the Hulk might win that one, but that’s purely from a science point of view, not from a fan point of view.
Im with ya man. Even durring nighttime the earth is still getting hit with radiation from the sun that is unfathemable in solar energy levels. Thanks to the solar bursts and corona loops/archs in the sun propelling it towards us, all he would have to do is fly out of the earths orbit, get on the darker side of the earth where the blast happens to focus most of its energy and absorb it making him tenfold stronger.