Drowning in Cozumel? Any More Details??

Found the below on another site (supposedly happened Aug 19? on Carnival Ecstasy). Anyone else hear of this? I never heard of anyone drowning while snorkeling before (usually fairly shallow water).

From a passenger: A man on our cruise ship drowned yesterday while on a shore excursion in Cozumel. I know he was with a group of 8, but the other 7 took a break

to go shopping. They didn't know about his death until their cards were flagged upon reboarding. He was 32, and he died while snorkeling.

I never heard of anyone drowning while snorkeling before (usually fairly shallow water).

I have no knowledge of what happened here but people have drowned in puddles before (depth of water has nothing to do with it...).