system
Given the following post, respond as if you're commenting on Reddit:
human
Water pressure around a submarine...

Hi, let's pretend there's a submarine with an opening on its bottom. No water can flow inside the submarine because of its perfect orientation without letting any air from the inside evade. To clarify my idea, it should look like a swimming pool from the inside of the submarine. Is this even theoretically possible? 

This submarine goes down to a deadly depth for human being. 

When someone from the inside of the submarine would climb into this "pool", would this person's foot be instantly crushed by the water pressure?


Wondering about this for a long time, I hope I was clear as English is not my mother tongue.

Thanks :)
gpt
As the submarine goes deeper and deeper, assuming it stays perfectly oriented so that no air can escape, the air will be compressed by water pressure. The volume of the air will shrink, making the "swimming pool" water level higher.

Depending on how deep you go, the pressurized air could kill a person.