My guess would be that the first attempt to rescue would usually be to turn off the filter and / or attempt to jump in and pull them out. I would think by the point anyone would think of and be able to access something to breathe through it would be too late.
Shittttt this is horrible. Is it possible to get someone stuck in this situation a pipe to breathe through or something??
I was also thinking about that but I guess he was already dead when they found him under water.
My guess would be that the first attempt to rescue would usually be to turn off the filter and / or attempt to jump in and pull them out. I would think by the point anyone would think of and be able to access something to breathe through it would be too late.
This is all speculation on my point though, idk