I looked up a depth to pressure calculator, at even 1300m, the pressure is 1892.67 psi.
"psi" is pounds per square inch, and a human has ballpark 3000 square inches of surface area.
So to get a (very) rough approximation, picture what would happen if you squeezed a human with 3000*1892 pounds of force. Or try not to picture it, because I imagine it being pretty gross.