It doesn't stop getting louder until it is very loud, and at that point, the helicopter is hovering a few feet above the parking lot, right out in front of Hiro and Vitaly's 20-by-30. It's a nice one, a corporate jet chopper, dark green, with subdued markings. Hiro suspects that in brighter light, he would be able to make out the logo of a defense contractor, most likely General Jim's Defense System.