THOR VS HULK-Fight Scene -The Avengers (2012) Movie Clip HD

How come in "The Avengers", when Thor and Hulk are fighting and the jet comes in to distract Hulk by opening fire on him, why does Thor jump out of the way? Does he want to give the fighter clear aim? I thought Thor was bulletproof.
There are a couple reasons for this. The first is pretty simple.

Thor had never been shot by a mini-gun before, as far as we’ve seen. He has potentially heard people talk about how people die when they’re shot, and so he would naturally assume that the weapon is dangerous.