If you watch many hunting videos and see the slo motion shots, most of the deer shot are reacting and dropping, it just happens so fast you can't tell normally, especially when you aren't even watching for that.
On an earlier thread, we discussed the sound of an arrow in flight, and different ways to quiet the arrow.
At least one person cited experience, A friend shot an arrow nearby, to excite him, as he stalked by. He said he heard it coming most of the way and it scared the hell out of him.
If HE could hear it. . . .
ChuckC