work would stop and try to find the source of the sound. is that happening now and are they hearing anything? everyone would get quiet. they would say everyone get quiet. remember 9/11? is that happening now? is it similar to that? >> absolutely. that is a standard procedure that goes on during a search e rent vent. you can see during some of the events, a few of the workers on top of the rubble pile, they're trying to place listening devices to be able to capture any kind of sound, moaning, tapping on a wall, and could mimic somebody trying to seek help. at the same time, you can see the rescue workers being able to pry up part of the pile, part of the surface. they call it delayering it. picking it up on one side, applying, cribbing and shoring to be able to keep that end open, and then able to send in their search k-9s to see if they're getting any hits on live victims. that would be followed by a