If the elevator is stuck down in the secret room under the VNC tower then you can use this method to manually get down into the room and finish the secret and/or send the elevator back up.
The steps if you're struggling to follow:
* Jump from high enough to paraglide into the wall right in the corner
* Immediately turn right once you're through the wall
* Stay left of the room with the yellow pipes
* Go underneath the ceiling you can see in front of you
* Swim downwards to land on the floor with the metal sticking through
* Run across to the wall in front of you and jump across towards the middle
* Walk towards the rocky elevator and crouch walk to fall through the gap