CLEAN : US contribution to Nepal quake response up to 22.5 million USD

The transcript discusses a rescue operation following a concrete collapse, highlighting safety concerns and the US Government's financial aid to Nepal. It details the provision of equipment and technical support by USAID, and the challenges faced in rescuing a trapped individual due to compact debris and noise interference.

Why would it have been nearly impossible to hear the young man calling out?

What challenges did the rescuers face in trying to locate the young man?