Theres also a neat little opening around 70 ft on the left side. It almost looks like it opens up after a sidemount restriction of around 20 ft long...
It does NOT open up.
The passage makes a bend to the right and continues for quite a bit as a restriction. I turned after spooling out to the end of my spool.
The danger with the passage is that both the ceiling and floor are soft clay. There are no line placements (i used a backup light stuck in the clay to avoid a line trap). I would not waste my time going in there since it goes to zero milk really fast due to your bubbles and your movement.
It then flows out into the basin within about 30-45mins so others don't like it when you waste your time in there either.