When BP helicopters are working a group, as in this case, they are often much closer to the ground than 100 feet. Tree top height is common, and at times they are only about 10 or so feet off the ground. It’s not out of the ordinary for a pilot to apprehend the group himself from within the helicopter. I have no idea how high this chopper was, but I’m wouldn’t be a bit surprised for it to have been within easy rock chunking distance. I too think that the pilot should have shot at the rock throwers, but chances are pretty strong that he had his hands full just trying to get the chopper safely on the ground.