When Jimmy reaches the top of the pit, the walls have not changed position as one of them would have.
The professor explains to the bad men that Superman had to leave his planet because it was about to supernova. Planets can not supernova, just dying stars.
A human body would not be able to stop a wall being driven by hydraulic pistons. In addition, Lois has her head is tilted forward so it would be driven forward until her neck was broken.
When Lois is being lowered into the pit by a rope she drops her purse in and you can hear it hit the bottom right away, revealing the pit to be very shallow.
When Jimmy is climbing horizontally out of the pit his jacket is hanging "sideways" toward his feet, showing that the camera is turned 90 degrees and he is simply walking with his hands touching the wall above his head.
Although it would be extremely difficult for most people to inch their way up a vertical shaft as Jimmy does, it would be impossible for Lois Lane to get out the the shaft that way.
When Superman levitates Lois Lane in the pit, the shadow of the levitation apparatus is clearly visible on the wall behind her.