Pulled each other under.....
When I was enlisted I remember DIs telling us during swim qual that when drowning, people will literally drown each other in survival panic and thats why it was so important to be competent in the water, especially for water rescues when trying to rescue a geared up and possibly injured Marine.
He said if they panicked and survival mode kicked in they instinctively try and climb you to keep themselves from drowning, effectively pushing you under.
Must be what happened here. Would have been fine id they separated and swam upwards, instead they panicked and drowned each other....
Sad.
When I went through boot that is exactly what happened to me. Whit man can't jump, black man can't swim. I stepped from dive board into the pool, slowly came to the surface only to have a large dark green recruit use me for a buoy. It seemed like forever me trying to fight him off. I'd come up he'd climb on top of me. I would go back under, this repeated at least three time until a couple swing instructors jumped in. The two of them grabbed him and pushed him under asking him how it felt. I threaded water and watched until they noticed me treading and yelled at me to finish swim qual. In my mind I thought I could get a restart but no. I had to finish after all that, I was literally exhausted when I got tot the end of the pool. The instructor on the end point in the direction for me to go which was successful completion of the course. Big relief.