Interesting story about how no one heard 2 children go to the bottom of a pool and pass out.

The kids were saved, though, because after the lifeguards did see the kids and pull them out, a nurse was there and knew how to revive them, even though one was unresponsive.

http://www.dailymail.co.uk/news/chin...nutes-CPR.html

This correlates with what I saw in 1 of the 2 rescues I've had to do. The kid went to the bottom of a deep spot behind a sandbar without making a sound.