The following is a screenshot from Sealab 2021, showing a tube erected upright on the ocean floor through which crew can exit and enter the station:
This isn't very consistent throughout the show, but Sealab's surroundings frequently appear pretty dim, so let's say the station is at a mesopelagic depth (200 to 1,000 m) of 600 m (the average)0.
This is too deep for diving without atmospheric diving suits1, so personnel operating at this depth with scuba gear as depicted isn't realistic because the pressure is too great.
But, in real life, if you were in the station in a room at the top of one of these tubes, what would the pressure of the water in the tube be like? Would the it be as great as just outside the tube, so that, the moment you dipped your toe in, your toe would be crushed as though it had a large piano pushing in on its every square inch? (That seems unlikely.) Likelier, it would be as low as at the ocean's surface, but, if so, how is the water pressure gradient distributed from the bottom to the top of the tube?
Gentleness with the physics appreciated.