One of my TA's agents had a client with a very dangerous situation a couple years ago. Drowning situation. She told me about it. So a lady & her hubby were snorkeling out in the lagoon when she actually inhaled -NOT swallow- water. She coughed & sputtered but was feeling okay. So then they continued on but she recalled reading where inhaling water was a really bad thing so the swam to a nearby lifeguard post. One of the ones out in the lagoon. She explained what happened & asked if they thought she should head in. The lifeguard totally flipped out. Immediately started blowing whistles. Jumped in the water & put her in floatation. Immediately hauling this woman in. The whole way she was like "What???? What?????" They immobilized her. Put her on a board. Running to get her back to the ship. She was unconscious before she got to the ship. She was medivac'ed back to south Florida. Basically it's a dry drowning situation. When you breathe water into your lungs it can be a little while or it can be pretty fast that your lungs react & fill with mucus. Dry drowning. Look it up. It's mostly seen with little kids who frolick & good around in water playing. Then after they're home the water they inhaled into their lungs drowns them.
Inexperienced snorkelers could be a factor in these. Just saying.