[montag813]

This is nuts. How would they compensate for tectonic plate movement?

Snorkelers will be distributed to passengers in case of "incident"*

*there may possibly be fewer snorkelers than passengers to avoid a cluttered appearance in the cabin

[Pikachu_Dad]

At that depth, think Titantic sub like implosion. You are going to need way, way more than a snorkel. And a way to get past the mountain of rocks .

[Tolerance Sucks Rocks]

Actually, you would need asbestos suits. The rift between the plates is an area of upwelling molten rock.