This is a view down through the open elevator of a Nike Hercules being raised to the
surface. (They were always launched from the surface, in a vertical position.)
You can see the aft section of the white missile, and the green painted booster cluster.
The elevator doors (diagonal stripes) were always closed for launching. The green iron work to the left and right are racks leading to other launchers. The missile could be moved along these "rails" to the other launchers.
When the elevator is raised, it goes up for several extra inches. When it reaches the top, it settles on four steel locking bars. The locking bars support the elevator for firing. Without the elevator being on locking bars, upon firing the downward thrust of the rocket cluster would drive the elevator and missile downward overcoming the hydraulic pressure that raised it initially. The locking bars also stabilize the elevator and enable the hydraulic control system to "rest".