Hope this helps. The reason why is when you drown in water you try to breath a lot so you stay alive and then a lot of water gets in so when you get out you loose a lot of air in your body so they give you air from their body so you stay alive and don’t die and they Also get the water out because the water has like oil and other stuff like ashes so they try to get out. I know I gave you a little extra fact but I didn’t google this and I hope this helps
